Tanning Mom Patricia Krentcil -- Glamour Pics Reveal Hottie Under That Hide

Brace yourself -- Tanning Mom used to be white, and kinda hot ... at least she was in a series of glamour pics she posed for in an attempt to break into the world of modeling.

Way back when TM, aka Patricia Krentcil, was in her 20s (think T-Rex) -- and before she turned her now infamous shade of leathery brown -- she took this headshot along with some cleavage-baring swimwear photos.

Krentcil, 44, has pled not guilty to child endangerment ... saying she never took her 5-year-old daughter into a tanning booth. The case has been sent to a grand jury.