I noticed that when using the auto-upload feature for photos and videos in Nextcloud, it compresses the files significantly. Photos are converted to JPG from other formats, and a 25 MB photo is reduced to 2-4 MB. This happens both when I use auto-upload and when I manually upload photos or videos. However, in my case (using an iPhone), if I save the photos/videos in the Files app and then manually upload them to Nextcloud, the files are not compressed.