Loving the control so far, excellent work 
Just a few things i would like to see, hope you don't mind
- Adding styles to the different elements of the control (different style for image name,size,description and actual image like adding a border)
- Controlling the page navigation alignment lik left,center,right; applying a style for that 'footer'; maybe putting the 'total images n' left justified and the page navigation right justified.
- Adding onmouseover/onmouseout for images (i have a nice image fade in onmouseover jscript i would like to use. Not sure if I can do this with codebehind))
- Displaying the orignial resoultion of the image
Possible bug, when the last page of a gallery has few images the spacing is a little strange (it looks like its trying to fit the images in the heigh/wdth that was given).
Keep up the great work