Your going to have to point to the datasheet and the schematic.
I did see a 0.1 uf cap for the POR circuit in a PIC datasheet.
It's customary, to place ceramic caps on the order of 0.1 uf near the power pins of an IC. These are called bypass capacitors. Without going into much detail, they could make a circuit more reliable and emit less RFI. Sometimes as many as three different types of capacitors are paralleled for the bypass function. For bypass caps, it's important to keep the leads as short as possible and as close as you can to the devices.
You don't want to use an electrolytic cap for the 0.1 uf bypass cap. That should usually be ceramic or Tantalum. Check the regulator datasheet.
C3 and I think C4 are bypass caps (If pin #1 of the PIC is power) and should not be a normal electrolytic cap.