if I try to create a bitmap bigger than 19000 px I get the error: Parameter is not valid. How can I workaround this??
System.Drawing.Bitmap myimage= new System.Drawing.Bitmap(20000, 20000);
Keep in mind, that is a LOT of memory you are trying to allocate with that Bitmap.
Refer to http://social.msdn.microsoft.com/Forums/en-US/netfxbcl/thread/37684999-62c7-4c41-8167-745a2b486583/
.NET is likely refusing to create an image that uses up that much contiguous memory all at once.
Slightly harder to read, but this reference helps as well:
Each image in the system has the amount of memory defined by this formula:
bit-depth * width * height / 8
This means that an image 40800 pixels by 4050 will require over 660 megabytes of memory.