please somewhat save me - layer cropping different size image issue

[rich2005]

Usually best to start with the largest image, so that subsequent layers do not fall outside the canvas size.

Can be fixed by Image -> Fit Canvas to Layers

Excess borders ? For a completed image, why not just crop it ? Or, if there are transparent borders, Image -> Crop to Content

Then for a layer, there is the same Layer -> Crop to Content

If you are getting white borders then somewhere along the workflow, add transparency to the layer Layer -> Transparency -> Add Alpha Chanel

All sorts of combinations of those. Some examples: https://youtu.be/KsJIa9rfSsc 3 minutes duration.