When I am trying to add a new pcture to portfolio section I get the message:

Warning: imagecreatefrompng(): gd-png: fatal libpng error: PLTE: CRC error in image_gd_load() (line 232 of /modules/system/image.gd.inc).
Warning: imagecreatefrompng(): gd-png error: setjmp returns error condition in image_gd_load() (line 232 of /modules/system/image.gd.inc).
Warning: imagecreatefrompng(): 'public://katalog005.png' is not a valid PNG file in image_gd_load() (line 232 of /modules/system/image.gd.inc).

Notice: imagecreatefromjpeg(): gd-jpeg, libjpeg: recoverable error: Corrupt JPEG data: premature end of data segment in image_gd_load() (line 232 of /modules/system/image.gd.inc).
Warning: imagecreatefromjpeg(): gd-jpeg: JPEG library reports unrecoverable error: in image_gd_load() (line 232 of /modules/system/image.gd.inc).
Warning: imagecreatefromjpeg(): 'public://katalog004c.jpg' is not a valid JPEG file in image_gd_load() (line 232 of /modules/system/image.gd.inc).

I tried with different pictures and result is the same :/ Please help me ASAP because I need update my portfolio. 

I was using van week ago adn eveything was ok, I didint change anything so I am suprised that I have this problem now :(((((