ThumbnailListItem and image loading

We want to load a thumbnail image from the memory instead of loading it directly from the file system such as

public ThumbnailListItem(string path);

eg: we have a lot of thumnail images embedded in resource file. we want load each image in a thumbnaillistitem. we notice that ThumbNailListItem has a method

public void SetThumbnail(Bitmap thumbnail);

public void Reload();

But we have not got it done successfully so far.

We want to do this in order to avoid opening many thumnail image files at the same time in hope to imrove performance a little bit.

Thanks.