Let's forgot Processor mode. We want to paint. Now, we select 8bpp or 24bpp mode. Next window - Max Size of Picture. PaintCAD asks you - which max pic's size you want to edit in this session (it is for stable work and special memory management). If you want to edit or create pictures with size equal of less than Screen Size - select Screen. But if you want to draw or edit for example 100010 pixels picture - then select 'Custom' and press right soft