BuddyPress.org

I am using WordPress version 3.2.1 . I have used buddypress plugin and custom community theme for managing the users, groups etc. There are number of groups(like as Facebook). In each group, the members can upload images. All the uploaded images of all groups are stored in same folder. Up to here, everything is fine.
Now I am designing a group page where the images uploaded in respective group will be displayed. Since all the images are in same folder, when I try to get images, I get all uploaded images(from different group too). I tried to distinguish images by their name but i couldn’t. Image names are like :: 1_0.025324001371613653_stefen2.jpg, 68_0.633952001324511516_268060_111305035632527_100002590944087_90672_1294454_n.jpg etc. The numbers 1 and 68 in the beginning of image name are the id of user or member who uploaded the image. But the problem is one user can be member of more than one group. So, if I distinguish the images by their first number(before _) then that image will be displayed in more than one group where the user is active.
I have checked in the database too. But there is only information about which user is in which group and which image is uploaded by which user. But, in which group the user uploaded that image is undefined. I tried to understand the upload code but couldn’t. I am beginner in buddypress and intermediate in WordPress.
Can anyone suggest me how to distinguish images???
Thans in advance!!!!