DotImage requires that there be contiguous open memory for an AtalaImage’s pixel memory. When this condition cannot be met an error with the following text will occur:

PixelMemoryException was unhandled
Failed to allocate  of pixel memory

This can happen in a number of situations if you think that you fall into one of these situations please follow the links for potential solutions:

• Opening many AtalaImage objects and storing them in physical memory (or a ImageCollection)
  HOWTO: Use Many Framed Images Efficiently
• Opening a particularly large single image and doing processing (ImageCommand.InPlaceProcessing == false) that requires having the image in memory more than once.
  HOWTO: Open a Large Image Rescaled to Prevent Memory Exceptions
• When using WorkspaceViewer or AnnotateViewer, avoid using the viewer.Images (ImageCollection) and avoid using the Open method.. if you need the Open functtionality consider using DocumentViewer or DocumentAnnotationViewer instead
• Trying to open an image with not enough memory. It has to be contiguous, so it is also possible that there is enough memory but the memory is “fragmented”, or very spread out such that there isn’t enough room to fit an image.
  Memory Defragmenters are available online and will provide variable results.

Original Article:
Q10258 - ERRMSG: PixelMemoryException: Failed to Allocate Pixel Memory