A few circular folds in my duodenum photo from endoscopy go halfway around, like a semicircle. several folds appear short. they go maybe 1/3, 1/4 or less of the way around. does this mean the folds are reduced, or normal variation in length of folds?

The doctor who did your endoscopy must have some reason to justify doing this test. Do you know the reason behind it? The folds that you saw in the photo of the duodenum are normal. The pattern of these folds has no significance and vary among different people. I would not be concerned on account of what you noticed. But your first source of information should be the doctor who did your Endoscopy.

What you have described is usually a normal finding on upper G.I. endoscopy. I recommend you contact the physician who did the endoscopy for specific advice and if any more tests or treatment is needed.