A long description make some trouble

[AgentCT]

I have some pictures with long description and a have the problem that these descriptions make some trouble. When you open the picture in a new window and you scroll down you see a big black background and only a small part of this black background shows text.

Is it possible to build in a teaser function and if the user want to see more of the description, he has to push a button and later he can see the rest of the description.

Thank you