Directional nature of the acetamido group in electrophilic substitution reaction
First of all, your second diagram concerning canonical structures are INCORRECT. There $\ce{N}$ has formed five bonds. $\ce{N}$ can't form five bonds because of unavailability of valance $\ce{d}$ subshells. It can only have the maximum covalency upto $4$ and how do you even think of keeping $\ce N$ atom neutral after forming five bonds which is anyway wrong. So, please make that correction.

There will be only one resonance structure:

(source)

Due to that delocalisation with carbonyl carbon, $\ce N$ will acquire a $\delta$+ charge which will increase its electron withdrawing effect (similar to $\ce{-I}$ effect) to some extent. Still, due to large no. of canonical structures of delocalisation in the benzene ring from the $\ce N$ atom, its $\ce{+R}$ effect is much stronger (strong $\ce{2p$\pi$-2p$\pi$} $ overlap) than its $\ce{-I}$ effect and thus the $\ce{-NHCOCH3}$ group still acts as an ortho-para directing group. But, its activating ability is slightly decreased from $\ce{-NH_2}$ group due to that $\ce{-I}$ effect.