Adobe Portfolio - thumbnails and image sizes

Hello,

My portfolio has become slower loading over the months. Especially scrolling with meanwhile 130+ images under one page gets tedious until all thumbnails are loaded. I am not fully understanding how portfolio works yet, so I'd like to reach out to the community with the following questions:

• If I upload an image, are the automatically generated thumbnails downscaled versions or the full versions just displayed smaller? The fact the images take long to fully load makes me believe these are actually not separate low-res versions but the actual original images. Thumbnails should defnitely load faster and the difference between 50, 100 or 150 should not be that significant ... or am I missing something? I've also noticed that the page only loads the immediately visible thumbnails and not the full page, one needs to start scrolling to trigger loading other thumbnails.

• In past years I have uploaded many images with width 1920px, but recently, after upgrading my camera and my monitor, I have also started uploading more in 3840px. Image sizes are now exceeding 10MB frequently. Is this overkill? At present, most of my expected viewers do not have a 4K monitor yet but it might change over the years, so I thought I might save myself the hassle of uploading/organizing twice (first all in 1920px and a few years later exchanging all files with 3840px versions sounds like a lot of effort). Obviously, this is a very subjective matter but I'd be happy to hear more opinions to see if I am in the same ballpark or on the upper end with my file sizes.

Side note: I only use Adobe portfolio as a hobbyist and am not depending on a perfect client experience for my visitors.