I just right-click copied a cover art image from one track and right-click pasted into another track, and the file size changed. The original image was X x Y 33k and the new image was the same X x Y but showed up as 287k. Is it not re-compressing the image the same way? (v2.39)
I did this copy routine via Mp3tag Panel and Clipboard as you described and I got a reduced cover size, for example 472 x 472 jpeg from 51.158 Bytes to 39.523 Bytes.
And - important - the target image has been corrupted!
The target image was shifted 3 pixel to the right and wrapped around.
This might be the same error like it has been reported some days ago here in the forum when copying image from Internet Explorer to Mp3tag Panel.
This is the corresponding thread:
[X] Cover Art distorted, 140x148 pixels instead of 140x140
The problem should be elevated to bug state.
I contributed to the thread linked above. I was still having issues with IE7 after it was confirmed to be working by Florian.
But I can say that the bug has been resolved as of version 2.39j. Thanks for the hard work on this!