Took these photos a few weeks back. We were south of ORD (Near BIGXX intersection), working our way between cells. Flew "formation" at FL260 & FL270 for about 5 minutes with UAL slowly overtaking us.
These shots don't really do the pictures justice, but I didn't want to post huge files here and didn't take the time to crop them to fit. If you want to see the "high-def" shots you can see them on my personal website:
Higher resolution (1728x1152) here
Medium Res
Low Res