When I use sprays in Garry’s Mod or Counter Strike: Source, the sprays come out with a white outline on every transparent spray I use.
Where the outline is most noticeable: Blurry Images (Shadows, Outer Glows, etc.) Around Black areas.
I’ve seen transparent sprays with shadows that are in great quality. It’s just me.
Here’s what I do: Create the image in Adobe Photoshop CS4, Create a new alpha channel and fill the selected images with white, and save as a TARGA. or whatever that file name is.