Hey basjack. Basically, what happened was the dip.png only goes to about 50% opacity, which isn't enough to trigger the alpha effect on it's own, but when i pasted it on top of itself a few times, it was enough to make it 100% opacity in the middle, which, when I used GET IMAGE, made that image have perfectly black pixels in it, which registered as transparent since I hadn't set the SET IMAGE COLORKEY to anything else than black yet. For example, code like this:
COLOR BACKDROP RGB(255, 0, 0)
LOAD IMAGE "Dip.png", 1
SPRITE 1, 0, 0, 1
HIDE SPRITE 1
SYNC ON
DO
IF BITMAP EXIST(2) THEN DELETE BITMAP 2
CREATE BITMAP 2, 200, 200
SET CURRENT BITMAP 2
BOX 0, 0, 190, 190, RGB(150, 150, 150), RGB(150, 150, 150), RGB(150, 150, 150), RGB(150, 150, 150)
FOR C = 1 to 10
PASTE SPRITE 1, 0, 0
NEXT C
IF IMAGE EXIST(2) THEN DELETE IMAGE 2
GET IMAGE 2, 0, 0, 190, 190
SET CURRENT BITMAP 0
SPRITE 2, 0, 0, 2
HIDE SPRITE 2
PASTE SPRITE 2, 0, 0
SYNC
LOOP
Hopefully this explains my facepalm. I wasn't even thinking that the problem would be with the resulting image. I thought it was with how I was using the original DIP image with PASTE SPRITE.
Because if you add the line
SET IMAGE COLORKEY 255, 0, 255
at the start of the program, you won't get the problem anymore
