Since I have personal knowledge of toddler clothes, thought I'd work this out for anyone worried about the size of the shorts...
Circo size chart:
24 month - 26.5-28 lbs, 33-35.5 inches (shorts in question were 24m Circo brand)
2T - 26.5-28 lbs, 33-35.5 inches
3T - 28.5-32 lbs, 36-38.5 inches
Carters size chart:
24 month - 27.5-30 lbs, 32.534 inches
2T - 29-31 lbs, 34.5-36.5 inches
3T - 31-34 lbs, 36.5-38.5 inches
So you can see that child clothing sizes (like adult sizes) are not uniform. A child might wear a different size in tops as in bottoms as well. So Cindy saying that Caylee wore a size 3T in the summer of 2008 doesn't really mean anything. Caylee would turn 3 at the end of the summer, so I'm sure Cindy would have bought her 3T clothing to grow into.
When my DD was 2 years, she was 25.5 lbs and 34" and at 3 years she was 29 lbs and 36.5". Assuming Caylee is roughly the same size (she looks like it from photos), she could easily wear a pair of 24m shorts at 18 months and the same pair of shorts a year later at 2 1/2. Cindy would not have bought Caylee a pair of 18m shorts for the summer of 2007, when she would turn 2 at the end of the summer, since you typically want clothes a child can grow into and wear for a while.