Select>Modify>Expand is inconsistent

[Stick Figure Art]

Can anyone tell me how I can expand/contract my line consistently by a set number of pixels?  The image is a before and after screenshot where I used select>modify>expand to do a 1 pixel expansion. I think the problem is fairly self evident but please let me know if I need to provide any other information.

Chris Warren

[PECourtejoie · Accepted solution]

Hello, I think that the issue is that you have semi-transparent pixels. Some will be above and below the 50% threshold, so might not count in the expand/contract.

[Stick Figure Art]

Thank you. That is exactly what is happening. When using the expand command it doesn't recognize any pixel that is less than 50% opaque.

When I expand my line, most times it's so I can either clean up or shade part of the image; OR, clone or clear a large area of pixels surrounding the image.

I'll have to rewrite my question explaining my end goal and resubmit it. Thank for helping me understand what's happening.