Images are compressed to a very low quality

I’m currently working on a photography site, and my images are 1500 px X 2250 px.
The images look fine in the designer, but when i publish they are very compressed.

The file size per image is around 2MB and should be more than enough for a clear image.

When i download the image from the browser I can see it has compressed to photos to around 30KB, that is way too low for an image to clear.

Any advice on how to fix this?

Here is my site Read-Only:

Hi. Take a look at this tip, I think it should work in your case.