Trouble with unwanted Offset

[levithanh337]

Hi there!

I'm trying to convert an image in a few steps.
It starts off as a 580x480 image and I only need 474x474 of those pixels.
So it goes from the original image, then it gets converted with a 474x474 circular mask (so now only the pixels inside of the circle are visible).
After that, I remove some colours from the image.

I'm certain the step that causes the offsetting is the mask.

Here's my steps:

convert ORIGINAL.gif \
MASK.png \
-alpha Off \
-compose CopyOpacity \
-composite \
-trim \
OUT.png

Does anyone have any suggestions to achieve the same result without offsets?

[snibgo]

If "-trim" actually trims, that creates offsets. Follow that with "+repage" if you want to remove the offsets.

Hint: Sprinkle "-write info:" anywhere you want to follow the progress of the changes. That would tell you where the offsets were added.