I know well the desire to show off the details upon which you labored; but uploading 8x12k 300dpi images in lossless format to the web is wholly unnecessary, unless you intend for your audience to print them on a lithographic press! If you do not give permission for such uses, you would be advantaged by rescaling your artworks.
Most monitors display at 72 or 150 ppi, at a resolution of 1920 x 1080 or 2560 x 1440. Your images need not be larger than this - particularly if they are thumbnails!
When your pages take over a minute to appear, there is an issue that will not be abated by a mere 'please wait for the page to load!' Most will click off before they ever see your work.