Why are these images so compressed?
While higher quality images are used in other areas, a lower quality image is used on Product tiles to decrease load times as much as possible since these thumbnails are only meant for initial reference and we load all of your Products at once.
This allows users on the Buyer and the Seller side to load up a page and see the full offering of Products quickly and navigate through it.
When the user generates a PDF or clicks into the product for more details, they are then able to see higher resolution images that provide more visual detail.
Minimize quality loss
Even though your images are compressed for Presentations, you can still minimize the amount of quality loss before the image is processed.
See Optimize Image Files for tips.