When you take a picture, and then move that picture to an album, it should show up in the album. Its possible that you're on the picture tab of the gallery. When you go from your camera directly to your gallery, it opens up the picture tab. This means that all pictures, regardless of whether they were taken by your camera, will show up newest to oldest. Try changing your tab to the albums tab - hopefully your image will be in the correct folder.
Hope this helps!
Yep, that's definitely a possibility. I do that way too often and my phone is just filling up with the same photos haha 😅
Thanks for the clarification and screenshot. I think that essentially means that the pictures you moved in are already there, and that trying to move them again results in a conflict of names(As @Tallman mentioned, thank you btw!) Try checking your album to see if your pictures are there inside of it already!