Hang on... The idea that he had other adventures with Rose not seen on screen (such as in the published books etc) is "bollocks", but the idea that photographs magically change isn't?

We know that in CE's season as The Doctor that there are adventures that happen off screen. Cue Mickey being so peeved off with the Doctor, Rose and Jack discussing where they've been.

i like the idea of the photo changing every regeneration, it kind of brings more mystery to the doc.

If having 'magic' in the show is a bad thing then we should get rid of the TARDIS and the fact he can regenerate all together The whole show is about things we don't understand - so i think the idea of the photo's changing adds to that which imo is a good thing

Those two are explicable within the sci-fi parameters of "advanced alien race with advanced alien technology". Photographs changing really aren't.

We do know that the Doctor visited Krakatoa in his 1st or 2nd incarnation as he mentions it in the Pertwee story 'Inferno' (before he got the Tardis working properly again so it cant have been incarnation 3).
But I cant see how his regeneration can affect a line drawing so I'd say the 9th Doctor revisited on a solo jaunt.
Perhaps if RTD had realised Eccleston was going to jump ship he would have written in some solo time for the Doctor - Rose spending the weekend with Jackie with the Doctor making himself scarce would have been very believeable!

Interestingly, Troughton looked in a mirror almost immediately after regenerating (in Tenth Planet/Power of the Daleks)...and Hartnell's face looks back!

Maybe Rose put the photos there as part of her "remote Bad Wolf graffiti spreading", to ensure that she'd see them back in her own time-line and thereby maintaining the paradox.

Or something.

But a line drawing being affected is no more or no less ridiculous than the chemicals on the surface of a photograph magically moving themselves around and changing colour!