thumb and microthumb sizes

[wkitty42]

what do you classify as a thumbnail or a microthumb?

what dimensions are actually classified as for these types of pics?

the reason i ask this is because i have my site set for the following...

normal pics - 640x480 (ie: longest edge to 640px)
thumbnails - 160x120 (ie: longest edge to 160px) [1/4th normal]
microthumbs - 64x48 (ie: longest edge to 64px) [1/10th normal] one factor for these settings is that my system is set to 1024x768 or higher for my video... i originally choose 640x480 for my normal pics because many folk were still using older systems that barely did 800x600 and a lot of folk have/had problems seeing things at higher resolutions so they generally didn't go over 800x600... however, with the cost of monitors having come down so much over the years, i know that a lot of folk with eyesight problems have moved on to 1024x768 displayed on 20inch or larger monitors which makes things physically large enough for them to see easier...

so, anyway... what say you? what sizes and methods do you use for these settings for display purposes? i'm not looking for any info on large stuff used for commercial prints (yet)... that may come at a later time ;)

[malum]

I use:

100x100 microthumbs
144x144 thumbs
500 longest side small pic
800 longest side large pic

default view is 500 pixels longest side with choice to see 800 pixel shot

[Pekka]

Thumbnail: a small image which lets you see an overview of the content of a photo (shape, subject, composition, color).
Microthumbnail: image for navigation, very approximate and associative (shape and color).

Neither should be big. If thumbs are too big, they are not clicked (what's the point, you already saw the photo!). So keep thumbs small enough, else you do not attract cliking for a bigger view. Microthumbs should be much smaller than thumbs (distinctive difference).