Fourth edition came under a lot of flak for its endless rules errata. If you kept up with all the updates, your copy of the PHB had scribbled corrections in each page. However, an errata document was never issued for the art.
On the cover:
The female wizard should not have her boobs AND her butt facing the viewer. Replace her with a Strong Female Character.
The male dragonborn fighter no longer has rivets in his armor shaped like lucky charms.
Erase the F tattooed on the female wizard's forehead. Change it to an A+
Replace the dwarf fighter in the background with a halfling thief (the party should probably have a striker).
Inside the book:
On page 22, Moradin should no longer use the same symbol as the Unitarian Universalists. They might get mad if their symbol is co-opted by an imaginary dwarf god. No, wait, we just checked with them and they're fine with it.
On page 34 (Dragonborn) move the male dragonborn one inch higher so you can't tell whether the female dragonborn has boobs.
The badass dragonborn in ruby armor on page 101 has been informed of the existence of the badass dragonborn in ruby armor on page 6, and has killed him and taken his stuff. The dragonborn on page 101 is now wearing the ruby ring. Page 6 should now have a picture of a dragonborn in an open casket, with a dwarf in the background leading a Unitarian Universalist funeral service.
On page 148, the warlord with seemingly unnecessary spikes on the right side of his helmet, on his left gauntlet, and on his right boot is now being threatened by a very tall monster to his right, a medium monster to his left, and a very short monster to his right.
Page 203, paragon tier feats: The picture of the fighter running away from a red dragon should be moved to the cover of the 1983 Mentzer red box.
You may draw supplemental belly shirt/sideboob armor on any of the female adventurers on the cover and on pages 4, 34, 40, 46, 48, 50, 96, 103, 129, 171, 191, 213, 234, 296, and 313, and on the male adventurers on pages 58 and 234.