Photos that are a 'highlight' in your album cover the full width of your album. If you scroll by the photo it will animate for you to be able to see the full image without scrolling too much.
Turn animation off
If you do not wish to have this animation you can turn this off. Click on the pencil icon to open the 'edit and enrich'-mode. Then click on the photo with the animation and uncheck the box saying 'animated view'.
Disable animation per photo
If you do not want these photos to be animated, you can switch it off per photo. Click on the pencil icon to enter the 'edit and enrich' mode. Then click on the picture with the animation and uncheck the box for 'Animated display'.
Animation for entire album
You can also disable the animation for all your photos in the album, you do that via the menu under the three balls at the top right of the album, choose 'settings' and then remove the check mark from 'show animations'.
Animation for all your albums
You can also disable the animation for all albums that you are still creating. Go to the profile of your account click on 'settings' and then remove the check mark from 'show animations'.
If you also want to apply this setting to your existing albums, click on your profile on the "Apply these settings to all albums" link.