Hello Stefan,
first of all thank you for this nice plugin, it has the potential to become a highly professional plugin. As a step towards this, I have some suggestions regarding the popup title and description window on image slides which would enhance the feel of the slideshow considerably.
1) When the mouse crosses such a slide very fast, then the description pops up full height and then moves down as normal. This is probably because in the "mouse leaves" event, the description popup starts from full height instead of the height it attained previously.
2) On top of that it would be nice if you could set a delay time for the popup, e.g. only after x=0.1 seconds after the mouse entered, the description box starts to rise. 1 and 2 would reduce the bumpy feel of a slideshow with a lot of such popup description boxes heavily.
3) I noticed an issue with small slideshows (height 150 in my case). There, always a small portion of the description box can be seen when the page is loaded. If you hover over with the mouse it opens up and then closes completely as normal. I can't post my webpage to back this up in the moment because it's not yet released and is password protected. But I can send you the password via email if you want.
http://wordpress.org/extend/plugins/slideshow-jquery-image-gallery/