We can already import pictures during the character creation stage, so that part is taken care of. Pictures for the other pilots maybe OK, but I fear even with hundreds of images we would see repetition. Perhaps being able to select the picture for other squadron mates could alleviate this, however as you say they tend to die rather quickly and have the chance to transfer, so it could become tedious.
Attributes for squad mates sounds potentially interesting, although I am under the assumption that they get better during each mission, but perhaps an addition to the AI in having a negative attribute, such as sickly, or a positive such as excellent gunnery skills may help.
Have you felt any competition with your squadmates? Someone else who is close to your score and always stays in touch with you? I had this recently with my Pup career, and one day he didn't return from a mission. The results showed he was credited with a kill, but was listed as killed with a line through his name and I honestly felt kind of happy...I guess I am a sick person lol.
Observers having their own names too, with the ability of the pilot, perhaps after gaining an appropriate rank, to choose who to take and again they will vary in quality. Plus it wasn't unheard of for an observer to switch into becoming a pilot, maybe add this as a possibility (he disappears and the re-appears a few weeks later as a pilot, not necessarily the same squadron though).
All these features will probably take years to get incorporated