How to release resouces used by a PictureBox and still use it

I have a program that uses PictureBox control to display a tiff image. The only property/method i am using for this control is the Handle. I use routines from a proprietary DLL to manipulate the image, basically display and merge text into the tiff image.

The issue i am having is that after about two hundred images have been processed, the program crashes and displays the message, "Screen-compatible bitmap cannot be created. The screen bitmap format cannot be determined."

If I reduce the amount of text that i add to the tiff image by half then i can process almost twice as many (almost 350+) images. Also if i add and use a second PictureBox control and switch to it after processing about 175 images i can process twice as many images in one run.
I think that the resources being used by the PictureBox contol are not being released.

If i use the Dispose method to release resources, i can no longer use the PictureBox control. I get the message "Cannot access a disposed object".

How can i release resources used by the PictureBox control after processing each image and still use it?

Any help is greatly appreciated.  Thank you.