Hi John,
Pic1 looks serious. IMHO, it's somewhat unusual to have cracks on the "compression" side of a crankarm. Most cracks start on the tensile side of the crankarm, where the tensile flex of pedaling actively propagates the crack. Of course, it's possible to have cracks start anywhere from internal flaws.
Peter Chu SF, CA
PS Do you happen to have a source for touch-up paint that matches metal flake silver Imron Trek 520? I tried mixing silver with glitter!