i have just ran wireshark through my network and i want to save only a specific types of packets for later analysis, this won't only make the packets found easier to find but it will also decrease the size of the capture file. can this be done if so how do you do it?

Did you just look? You just select the radio button in the save dialog to choose the displayed packets.

I have just saved the filtered packets that i was after and when i opened the file in wireshark and all of the packets that i was going to examine were mal-formed.

i am running wireshark to capture jpeg files across the network for experimental purposes and when i saved the file with only the viewed packets to be saved it malformed the pictures before i could even try to re-compile them. if it is possible can you apply a filter that will collect only the packets from the filter without capturing everything since saving the filetered file makes the pictures malformed i want to see if wireshark can only capture specific packets so i can save them as normal and only have the picture files

Wireshark requires an X server, a Desktop Environment and all dependencies. To capture traffic you don't need that. Try the command line equivalent tshark, rawshark or tcpdump with a BPF filter if you're losing data due to fragmentation or capture performance or try tcpxtract.