Each album that you create has a maximum of 7,500 images or videos. The only album that doesn't have a limit is your Mobile Uploads album.
If you try to upload an image or a video to an album that has already reached its maximum limit, it will not upload. In this situation, you will need to create a new album or a new sub-album within that album to upload the images.
Alternatively, you can upload the images to a different album that has not reached its maximum limit.
For instructions on creating a new album or sub-album, click here.