If your visitors are making much use of the text link, maybe it shouldn't be where it currently is, you know?
I think you mean "aren't" instead of "are".
Hmmm.... It is in the first paragraph of content, so I am a little hesitant to move it. However, I will look to see if there is another part of the text where it reads better.
Can you add text link to the thumbnail so that both image and text appear in a single anchor element?
Yes, I do have some text in the anchor element that wraps around the thumbnail. My concern is that the text in that element is not optimized for anchor text - it is more of a sentence-long description of the picture (i.e., a caption), and not a two-worded keyword phrase (which would be optimum for anchor text).
the alt text for the image link is a description of the contents: "this is a photo of a widget base displaying the XYZ attribute." (where the words "widget base" would be my preferred keywords).