Pretty much any commercial graphics editor you get will handle this very
well. Here's a quick (but by no means comprehensive) list. These all have
free trials:
Paint Shop Pro - www.jasc.com
Adobe Photoshop Elements - www.adobe.com
Ulead PhotoImpact - www.ulead.com
If you have an existing file you want converted to .gif (or any other
format) try the free IrfanView program. It's a great little utility that
anyone doing graphics work should have on hand: www.irfanview.com
