Please check the following links if want to save some hassle of writing scratch MAK files, and having to edit DOS prompt commands all the time.

MAKmak Beta. - Just a fun project me, zip and gannon worked on. It uses VERGE to open old CHR files or almost any image file, which can then be exported to files that chrmak5.exe can handle (a BAT file, and a BMP).

VOpenCHR. - allows editing of all CHR formats, and saving directly as CHR formats, instead of annoying MAK files. Probably the better of the two.