I need to convert tif images so that I can use them on the web, but if I change them to gif or jpeg, they lose some of their sharpness. I'm using photoshop 5. Any suggestions?

.gif images use a compression algorithm called Lempel-Ziv-Welch or LZW, which is considered a lossless format because the resulting decompressed image "looks" exactly like the original. Most of the problems people have with this format are due to using color palettes that result in "strange" display results. If you are wanting to use this format in Photoshop you have to install the Gif98 plugin.

.jpg or jpeg is a raster image format created by the Joint Photographic Experts Group (now you know where the acronym comes from <grin>). Jpeg compresses by separating out the hues, keeping a black and white image and compressing the subtle color differences. Jpeg is a lossy process due to this even when used on the highest quality settings in Photoshop.

tif images are not compressed and contain all of the original image content.

I have long been of the personal opinion that .jpg files are a little better due to the fact that they produce small files while allowing control over image quality.

All of this compression is a give-and-take scenario. You need smaller files so you can display them on web pages, but nothing is free.

One option you have for .jpg option you have under Photoshop to increase the resolution is to select a higher quality in the image options dialog but this will result in a larger file.

For more in-depth discussions of images check out "Creating Killer Web Sites - Second Edition by  David Siegel" or any of the "Web Graphics series by Linda Wienman"

Bees