Ok first take it out after powering off the fone and clean the little gold edge connectors on the micro sim with a small piece of cloth ... perhaps with a little alcohol. Next put it in ... it should click when released and move back slightly when inserted all of the way in.
Power up the fone ... if you can't see the files you want on Gallery then you might need to reformat it.
BUT ... the best bet then is to take it out, put it into a reader hooked up to a PC or Laptop and try to see the files on it ... then copy them off.
Reformat it from the PC / Laptop and try it in the fone again.