What we all know happens when attempting to use lazily-made masks:

Here I'm going to explain in detail about fixing these lazily-made masks:
- example


Step 1:
After opening a broken mask, you must change the mode to RGB before making any changes to the image:

Step 2:
Select "Magic spell" and set "Adding" mode. So now you'll be able to click on white zones which means "transparent":

When all the white zones have been selected, click the "Delete" key to fill them with "real" white color (must be #FFFFFF):

Step 3:
Do inverse of selection:

After inversing, DON'T forget to swap foreground and background colors! (Now black is needed as the 'background')

Step 4:
Now when you've done all this, press the "Delete" key and your mask will be done!

Step 5:
Now you could switch back to indexed color mode (which is needed for GIFs)

The image must be Black&White or gray-grade

After you're done with all of this, you have to overwrite the source image: (File->Overwrite "xxx-YYm.gif" or "Export to..." and save them as GIF)

Another example:
- Before

- After

Sprite-designers, please don't make lazily-made masks next time!
And save files as the real .GIF, not .BMP renamed with the .GIF extension







