I was having the same problem - medium gel's being a tad too small & the large ones being a tad too big - so i started swapping tips/sleeves/foamies/flanges/etc from some of my other IEMs & found the following tips to fit perfect:
- Shure's SE- series sleeves (& most of their E's, i's & SCL's)
- Sleek's SA-6 flanges
- Futuresonic's Atrio M5/8 plugs
&
- Comply T-100's - P's also, but you'll need to force them just a little..
Personally I like the Shure EABKF1-10 (medium)'s best, they are practically the same size as the Comply t-100-/P mediums, but to me these feel just a bit more luxurious (they're more conical so they suit me better), & they're black..
I also find these foam type tips to reduce quite a bit of microphonics (or it's the thin-nes of the Klipsch gel that enhance microphonics?), plus they increase the the depth of the lows a little more to my liking.
The slightly thicker double/triple flanges I found to be nice fitting & sounding aswell but because
i'm not using X-10's but Custom-3's they are just too long (they make the Custom stick out too far), but my guess is that they will fit the Image's just fine.
According to Klipsch' tech support the Image's & Custom's use identical gel's, so not to worry.
