Seriously, one of world's largest image banks - Science Photo Library - provides a breathtaking resource for scientific image needs. On the other hand Leuku-archive in Finnish Lappland provides top quality ordinary images by renowed Finnish nature photographers.

I include here some guidelines to order images from my site:
1) Please, identify image by its name. In most cases it would be helpful if you included the thumbnail (thumbnail; not the larger image) within the message, too. I'll take care of that we are talking about the very same image.
2) If you have deadlines, please, let me know.
3) Let me know the required dimensions either in pixels (height and width), or tell me the printed size and I will scan image to 300 dpi. All still material on this site is originally photographed with ordinary 35 mm slidefilm. Scans can be up to size 3600 x 5400 pixels.
4) In most cases using JPG-format (with the compression factor 12 in PhotoShop - guarantees the best JPG-quality) is enough and allows using e-mail attachement (5MB limit). In critical cases I can load larger file to my site and pass the address for instant copying. If you need to mail "large" files to me, I have to tune the max limiting size accepted by my mail. Usually the max size of the mail is hovering around 200 kB.
5) Files have either sRGB- or in Adobe RGB 1998 -colourprofile. When image is opened this info should appear in the application. Keep in mind that image has been tuned using corresponding profile and it should not be just neglected. If you require some other profile, manage colours with the application program. My Trinitron monitor is calibrated to 6500K.
6) In all cases hi-res image looks a lot better than the small one posted in these pages!