Hi @Sven_Erik_Slattedale, thanks for reporting this. I checked from our support desk but could not any earlier report on this. I am taking a look, thanks for your patience in advance.
As a side note, images that are uploaded are automatically converted to responsive variants. Normally it is possible to disable responsive images for a specific image:
If you want to regenerate responsive images for all images on the site, then you can trigger that by typing CMD+SHIFT+i (CTRL+SHIFT+i on Windows) and the designer will scan and re-measure all your images on all pages for you.
See more here: https://university.webflow.com/article/responsive-images
Can you help to give more info on the trouble, are you uploading an image and it is not being converted to a responsive variant ? Do you have the link to the published site where those variants are used/shown?