fix crash with some filenames (windows)

[srirams]

I'm having some crashes in windows with some (maybe corrupt) filenames:

like:

Chapultepec_ Ciudad de M�xico_Mexico City

this patch fixes it.

also, sometimes when scrolling fast through a lot of images, it crashes, and the second commit fixes it.

[easymodo]

Hi. Sorry for taking too long Briefly tested this, looks like 1st commit breaks stuff on linux. Merged the 2nd one for now