Paint chops off bits of images? That's a new one on me. I use it for most of my image editing, but when I want to save a GIF file, I copy the result to Paint Shop Pro 7 and do it from there. Paint just has terrible GIF support for some reason. I really don't know how Microsoft managed to do that, it must be some part of their war against standards or something.
About the time I first wrote my GIF handling code (back when I was using QBasic), I also tried my hand at a BMP converter. Unfortunately I couldn't find a program which would output file headers that matched the standards documentation I had, which meant I couldn't get a good grasp of how the format worked. I'll write one some day, though.
Anyway. I downloaded The GIMP and had a go at saving a GIF with it. It's a little odd to use, but I came up with these steps -
1) Open the GIF you want to edit. GIMP will probably complain about my GIFs, but it'll open them regardless.
Hold Shift+Ctrl+A (de-select all), then Ctrl+C (copy). You can now paste the image into Paintbrush, or whatever program you prefer. For some reason, using Ctrl+A (select all) does result in a cropped image when you paste to Paintbrush. Don't ask me why. Also, it's best to drag the image size in Paint down as low as you can get it, that way when you paste, the image size will match what's on the clipboard exactly.
2) Edit the image as you see fit, select it, go back to The GIMP and paste it.
Press Z to highlight the magic wand tool, then click on the grey space around the image. Hold down shift, then click on each of the areas you want to become transparent.
3) Hit Ctrl+K (clear) to wipe out the unwanted zones. They should now appear as a grey checker board. If they do not, select the Layer menu, scroll down to Transparency, then select Add Alpha Channel from the sub menu before hitting Ctrl+K again.
Click once more in the grey area around the image to clear your selections.
4) Hit Ctrl+Shift+S (save as), click the little plus next to "Browse for other folders", and find where you want to dump the file.
Type in a name, give it a .GIF extension, hit Save, and then Export. Untick the "Gif comment" box (though I'm pretty sure my software doesn't care one way or the other), then hit Ok.
Hey presto, transparent GIF. Hopefully this should help you.
I surfed around a bit more and discovered Paint.NET
, which requires .NET 2.0
(as opposed to 1.1, which is the minimum required for Daishiva's stuff). This program works a lot like the Microsoft version of Paint, but seems to be much improved.
All you need to do is dump the image in it, use the wand to select the areas as you did in The GIMP, then hit delete to clear them. When you go to save it as a GIF, max out the transparency levels, and minimise the dithering levels.
Note that Paint.NET doesn't like my GIF files at all. I guess they really do need work. You'll need to first open them with The GIMP, then paste them to Paint.NET, until I get the code sorted out.