I'm testing out how images look from the new portfolio system. It appears that if you use the link provided under the photo you get the following:
However, if you click on the image to see it in the lightbox, and then use right click and properties to get the URL at that point, then you get a much better version of the photo without the JPG artifacts of the re-compression. Here is what that looks like.
Compare the two photos to see the difference.
The problem is easy to solve. Just use the URL that you copy from the main photo and then paste it into the dialog box after clicking the yellow icon, and then edit it while in that box to remove the /large and that will give you the actual image as you uploaded it.
Note: You can also use the "New Portfolio" selection that is to the right of the box where you type your post to select the photo. It is still cumbersome to use, but it will also give you the "/large" version, so you would need to edit the "/large" away to get the better resolution version.