[Q] Media Viewer: Enable thumbnails, but show original photo when enlarged?

Hi, I hope I’m posting this in the right place. I’m scouring the web to find a selfhosted photo storage option, and among the top candidates are owncloud and nextcloud, which are pretty similar as far as I can tell.
I currently have a nextcloud instance set up, but my problem with it is the hard choice between

  • enable preview generation for thumbnails, but then the user sees a photo that is not the original (but an image of arbitrary dimensions and arbitrary jpeg quality), OR;
  • disable preview generation, so the user sees the original photo, but now there are no thumbnails anywhere in the system.

In my setup there is a nice little script that compresses original images down to <1MB and keeps perceived quality intact. I am not starving for bandwidth, so displaying these 1MB pictures makes more sense to me than displaying a preview that is of worse quality than my original image, and likely at least comparable in size to the original.
I was hoping to find some details about whether or not this same issue exists with owncloud? But I can’t find much documentation available on preview generation and how the images are displayed.
Best regards