Cracks in My Home

I have been working on patching some different rooms together in GIMP and some rooms are coming together quite well but I am having quite a few problems with my office and living room. They have ended up with cracks in them. I am attaching a screenshot so you can see for yourself and maybe give me some ideas about what I have done wrong. Thank you!

Hi Beth, the original maps are 512 pixels by 512 pixels each and so the modded ones need to align with them. I've had a few of those issues in the past as well.

Thanks Miss Kathy! I have since fixed them. I am so happy to be able to do this on my own!