If I had to guess, I'd say the picture is mis-captioned. It looks more like a ground explosion to me.
If this is the 406th (Fighter) Group, they were actually trained as dive bombers and engaged regularly in strafing, close support and dive-bombing runs.
That said, they did fly escort, too.
No mention of the photo or a Captain Walsh at
this website of the 406th. I'll keep looking a little more.....