LazyCam is probably not the best tool to use (but it is possible to create the Gcode for an image with this).
As said, it depends on the type of image you require to engrave and how you wish to engrave it (rotary, impact, laser, etc.).
Just sticking with Arsoft products...
Excellent 3D (2.5D) reliefs and lithophanes can be produced with Mach1Filter.exe ( a long forgotten tool - even Art forgot he wrote it
)
Excellent Line Art, Shades of Grey and impact engraving can be produced with the Impact engraving / Laser plugin (my favorite).
A forum search should provide more details and reproduced images etc. from both of the above processes ( and, of course, they are both free
).
Tweakie.