Does anyone know, how I can get thes GIFs and JPGs in my applet transparent (define a transp. color) ?? I often see that in applets on the net, but I can''t do that myself....

I think you need to make a transparent gif, some programs let you convert normal gifs to transparent gifs. It is harder than it should be but it can be done. As to whether they work in your code, I have no idea.

I have CorelPhotopaint and Adobe Photoshop 5 (and MSPaint ). Can I create transparent gifs with them ? Don''t know how...

Transparent Gif making in Photoshop 4:
First of all, its in the instruction book.

Make an image
flatten it
convert Image>Mode to indexed color
save File>export>gif
then select the color to be transparent