Which is better for thumbnails - GIF or JPG?

[sun818]

Can both do interlacing?
Can both formats show black/white previews?

I unfortunately had to use a dial-up modem this weekend to work and see that the web is "bloated" with a lot unnecessary graphics. But if they are going to be, why not make the dial-up modem experience a little better?

So, which graphics format do you think would work best for dial-up modem users in terms of file size and image quality?

[crashomon]

Interlacing is a gif only detail (I believe)
As for b/w preview, in photoshop you can switch mode to see what works (however, it deletes the color information in some instances), but why use bw unless you want to confuse the user?.

Generally you want to keep the files in the same format (at least from a photoshop perspective). Its also easier to name files big.jpg and small.jpg instead of trying to remember big.jpg and small.gif (or was it big.gif and small.jpg?).

IF the thumbs are truly small (less than 100 x 100) and they have only a few main colors, then you can go with a gif. Otherwise stick to jpg for flesh tones or intricate images with a lot of detail.

review lynda weinman's book "designing web graphics" or a good photoshop tutorial for further details.

good luck,

Patrick Elward

[benihana]

re: interlacing

jpeg has 'progressive' which essentially does the same job, but starts blurry and gets clearer

[paybacksa]

the GIF writing patent is set to expire in early July of 2004, so that should also change some things....

[sun818]

> b/w preview

I did not mean the entire thumbnail is b/w. It just means as part of the "progressive" loading of the image file, it first shows the image as b/w then loads color as the file loads.

Is "progressive" JPEG supported on all modern browsers 5.x and up?

[benihana]

>progressive support

ive never *known* it not to work.

[Leosghost]

I use IE 5.5 ( won't put more recent on any machine due to phone homes via broswer ) ..progressives work just fine ........jpeg quality depends a lot on the algo used ..