Only just saw your Edit, brilliant I'm really happy that I could of helped but feel free to post any further questions you might have and I'll do my best.
And I also know why there's black borders, there's additional animations for sprites, like car doors opening etc and if you were to go thru all the images (such as a ped walking) you'd probably see that all the pixels get used eventually across all the frames of animation etc
because animations must be stored in an array of images of exact dimensions, you'll have some frames that don't seem centred etc
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