A big boar stands 18" over a 55gal drum laying over. A big boar stands taller than a 55gal drum upright. Since I began baiting in Wyo in 1995 I have never seen a big boar come in except after sunset and darn few then. When I saw them, there was NO doubt they were big.
The hardest animal to judge is a bear and if you weren't sure if it was big enough, it may not have been. I'll admit, it appears to look big in picture, and may be, but when they look to have short legs and back end is higher, they are usually sows. Boars look "square".
But I could be wrong.