Picture type affects size when inserted into Word 2007?

[calvin-c]

Why does Word display the same size pictures at different sizes depending on the file type? The attached .zip contains a folder with duplicate images, one in .JPG & the other in .GIF, both the same dimensions. It also contains a Word document with those images inserted into a table.

Although the table is obviously messed up starting in the 2nd row the problem is actually the differently sized pictures as shown in the 1st row.

To continue with the project I can convert all the .JPG images to .GIF but is this a known issue with Word? Why does the image type change the displayed size? Thanks.

[fumei]

I suspect it is because GIF files are limited to 8 bit, and JPG are 24 bit, EVEN AT THE SAME PIXEL DIMENSIONS. Therefore JPG size up differently. Remember display is completely the result of the printer driver. It could be that the driver sees a 600x400 (say) 24 bit file differently than a 600x400 (say) 8 bit file. So even though they are both 600x400 that is irrelevant to the way the printer driver interprets things.

[fumei]

OK, I just tested this (as I never use GIF anyway, so I had to actually check). First of all I confirm the situation as you describe, and yes it is directly related to the bit depth. If you use the same image (they have the same dimensions), one a GIF and one a JPG, you can SEE the visual relationship. And sorry, there is no way around this. It is inherent to the file types. In other words you have to make a JPG 3 times the pixel dimensions to match a GIF in the display.

if the image is (say) 640x480, then you have to make the JPG image 1920x1440 to look the same as a 640x480 GIF. Which is exactly what you would expect moving from 8 bit to 24 bit. Oh, and it has nothing to do with Word version, as this affects all versions, and most likely all applications. Although...hmmm...I would have to test that.

[fumei]

Nope. Powerpoint does NOT do this, again I suspect because PP does not use the printer driver to figure out display. It works directly with the video driver. ANOTHER reason to stop thinking of Word as a layout application.

BTW it may help to things of it this way. Yes a 640x480 pixel dimension (GIF) has the same number of pixels as a 640x480 (JPG), but the GIF pixel are three times as big. Or more accurate, because each pixel in the JPG holds three times as much information, it is three times smaller.

[macropod]

In Word, pictures are scaled according to the # pixels width & height. It has nothing to do with the bit depth, but with assumptions Word makes about different file formats. GIF images, for example, are typically used for screen display and Word thus treats them as having a 1:1 image pixel:screen pixel relationship. On my system, therefore, a GIF image gets inserted at 96ppi. JPG images, though, are typically designed for print and, unless they have been given a specific resolution attribute, are inserted at 120dpi. In both cases, though, the nominal resolution may be well above that due to Word constraining it to fit the available space. For example, I have a 748*1062 jpg image. In portrait format, it gets inserted full size (15.83*22.48cm [w*h]) but in landscape format, it gets reduced to 71% (16*11.27cm [w*h]).

[calvin-c]

I'd prefer Word not to scale the images at all, that's why I resize them. I'm not sure what's meant by 'specific resolution attribute' for JPG but from context that means setting the dpi. I'll see if that changes things. For this project size isn't an issue as long as Word doesn't change it differently for different images. I remember, a long, long time ago, sending a 640x480 image that filled my 14" screen to the printer-and finding it 'reduced' to (approximately) 2"x1.5" on my 600dpi printer. That was my introduction to the difference between ppi & dpi. I'm glad that modern programs handle that distinction for us. Except for Word, of course. Thanks.

[macropod]

I'd prefer Word not to scale the images at all
Giving an image any size necessarily means there is some scaling, be that a 0.5pt*0.5pt size (the smallest Word can handle) or a 1584pt*1584pt size (the largest Word can handle). Like any graphics program, Word applies an algorithm to display an image. Unlike graphics programs, though, Word recognises that the image needs to fit within the page margins; something no graphics program has to consider until print time. Bear in mind, too, that images have no inherent pixel size; 600dpi and the like are printer properties, ordinarily not image properties.

[fumei]

Are you about this Paul? Certainly there are insertion adjustments if the portrait vs landscape format does allow "native" size.

On my system, therefore, a GIF image gets inserted at 96ppi. JPG images, though, are typically designed for print and, unless they have been given a specific resolution attribute, are inserted at 120dpi. You seem to be equating PPI with DPI.

Secondly, I do not know what you mean by "given a specific resolution attribute". ALL bit-mapped file have a "specific" resolution, that is DPI.

However, I do think you are somewhat correct. If you insert a 300x300 GIF @ 96 dpi and a 300x300 JPG @ 96 dpi, they are identical in a Word document. You seem to be saying that the GIF is mapped 1:1, but the JPG would not be. This is, in the test I just did, not the case. They take up exactly the same amount of real estate.

Word inserts both JPG and GIF exactly as that file is set up as...if it can. If it can not, THEN it does a change to fit. But I find no difference by file format by default. It seems to treat GIF and JPG the same.

Bottom line though I was full of crap as usual. DPI rules. Bit-depth can be an issue, but DPI rules to start. It is simply that GIF are rarely higher resolution.

[macropod]

You seem to be equating PPI with DPI.
Sorry, the '120dpi' should have read '120ppi'.

ALL bit-mapped file have a "specific" resolution, that is DPI.
No, pictures don't have any "specific" resolution - they're nothing more than a collection of pixels; it's up to the processing app/user to determine the ppi and/or dpi. The same image, depending on what size it's printed at, could be printed at 1dpi or 1200dpi.

If you insert a 300x300 GIF @ 96 dpi and a 300x300 JPG @ 96 dpi, they are identical in a Word document.
Agreed, but you usually don't get to choose the dpi - Word does that for you. In my testing, a GIF image (scaled to 100%) displayed at 96ppi but a JPG image at the same 100% scaling displayed at 120ppi.

[calvin-c]

Giving an image any size necessarily means there is some scaling If you say so I'll take your word for it but it doesn't make sense to me that Word would scale an image that already fits onto the page. The potential is always there but why would Word invoke it if the image already fits?

I'm a little confused about your last post but no matter, I think we're running into limitations of English. To me, the size & resolution of pictures mean the pixel dimensions. If you think of 'resolution' a fine or grainy though then it depends on the device. I remember the early Macs that had such 'better' pictures than PC's. Few people seemed to understand that pictures always look better at 5" than when enlarged to 14". Until they decide to print them, that is-then they understand. What's so different about understanding it on a monitor?

Anyway, no problem here. I think I followed enough to understand what you're saying about how the dpi affects the size at which Word displays the picture. I haven't found a way to set the dpi, yet, but it's probably there. Someplace in Word, I assume, since setting the dpi in the image file doesn't make sense. "inch" really only applies to physical objects, be they screen pixels or ink dots. Image pixels are logical elements.

[fumei]

By specific I mean that any image file (GIF or BMP or JPG) has a resolution set. That is, if you bring it into a graphics application you can see what DPI it is set at. That is specific. It does not float. An application can CHANGE it, but that is a change. If you copy it to another computer and look at it again in a graphic app, the resolution is the same. If you look at it in a different app (say Corel versus Photoshop) the resolution will be the same...until of course you CHANGE it. So no, you are wrong, pictures (image files themselves) DO have a specific resolution, that is, the file itself HAS a resolution. Otherwise the image file would have...what...NO resolution???? I do not think so.

The same image, depending on what size it's printed at, could be printed at 1dpi or 1200dpi.
Yes true, but only by changing it!

they're nothing more than a collection of pixels;
Yes, but do this: make three image files (say JPG, but it does not actually matter) in Photoshop.
1. 300x300 pixel at 96 dpi
2. 300x300 pixel at 150 dpi
3. 300x300 pixel at 300 dpi

Bring them all into Word. They are NOT going to look the same. The "collection of pixels" are identical, and Word is NOT determining the dpi or ppi. Word always brings in image files AS THEY ARE, unless it can't fit them. Then, yes it makes changes.

No you do not generally choose DPI. I do not know what you exactly by "scaled to 100%". If you bring in a image file via Insert Picture -and nothing else - and it is small enough that no scaling is done in order to fit, does that mean 100%.

[macropod]

By specific I mean that any image file (GIF or BMP or JPG) has a resolution set. ... Otherwise the image file would have...what...NO resolution???? I do not think so.
Strange though it may sound, the "NO resolution" is exactly what I mean. How, for example, would you define the resolution of a vector image? And how about an image taken by any digital camera? Their 'resolution' is typically defined in terms of megapixels, but those have no particular connection with any printer's dpi or screen's ppi.

do this: make three image files (say JPG, but it does not actually matter) in Photoshop.
1. 300x300 pixel at 96 dpi
2. 300x300 pixel at 150 dpi
3. 300x300 pixel at 300 dpi

Bring them all into Word. They are NOT going to look the same. The "collection of pixels" are identical, and Word is NOT determining the dpi or ppi. Word always brings in image files AS THEY ARE, unless it can't fit them. Then, yes it makes changes.
Actually, in this case, Word is reading the dpi metadata from the image files to determine the scaling; most images (e.g. an image taken by a digital camera or any vector image) don't have such data, though.

I do not know what you exactly by "scaled to 100%". If you bring in a image file via Insert Picture -and nothing else - and it is small enough that no scaling is done in order to fit, does that mean 100%.
By "scaled to 100%", I mean as you've surmised. If, having inserted an image, you look at its scaling via the Picture Size dialog, you'll see horizontal and vertical Scale values. If they're 100% that's Word's default scaling for an image of those pixel dimensions in that image format (GIF, JPG, etc.).

[fumei]

Strange though it may sound, the "NO resolution" is exactly what I mean. How, for example, would you define the resolution of a vector image? Ummmm...we have been talking about bit-mapped files, not vector.

Actually, in this case, Word is reading the dpi metadata from the image files to determine the scaling; most images (e.g. an image taken by a digital camera or any vector image) don't have such data, though. Not true. Again, vector...no. However, I just checked 25 different files from various digital cameras (I have four different ones ranging from 7 megapixels to 18 megapixels) and, they all have the equivalent information as if I create a JPG from scratch. They are either 72 or 180 pixel per inch. All of them. This has nothing whatsoever to do with the megapixels. A JPG shot with the 7 megapixel is 72 by default, as is the 18 megapixel camera. They are identical. If you create a bit mapped file from scratch (before saving as any specific file format), Photoshop for example defaults to 72. You are incorrect, digital camera files are no different from bit-map files created by say Photoshop. To be clear though, I am not talking about RAW files. They are, like vector files, data files. Somewhat like MIDI files are not sound files, they are data files.

All bit-map files have a resolution...not "no resolution". That applies to files from a digital camera. Vectors, no they do not have a resolution, that is what makes them vector.

[macropod]

The 72dpi setting is merely assumed when nothing else is specified, rather like the defaults that VBA assumes for much of the coding you and I do. No-one I know of would be happy with getting a 6ft x 4ft printout as the default from an 18MP camera (Canon 600D/60D?) just because of an assumed 72dpi/ppi resolution.

Anyway, this all seems to be getting away from the thread topic - why different format images are treated differently.

[fumei]

What does happiness or unhappiness have to do with anything? All I am saying is that if I open a file from my 18 MP camera (yes a 60Da - the "a" is because it is a special model for astronomical purposes; it has a modified IR filter) in Photoshop the document size is 72" x 48". True, I would never print it like that; I would change the dpi to squeeze more dots per inch.