The club posted the quartet of images on their Twitter account on Tuesday, with the winger - signed from Tottenham on loan - looking like he would rather be anywhere other than Finch Farm.
However, Martinez insists Lennon is happy to have arrived on Merseyside, and that he has seen a determination in the England international.
"I would blame the photographer," the Spaniard quipped. "It's your job to make him show a nice smile to the picture.
"I saw a different face. I saw a focused face - one that he was ready to train and ready to perform.
"It's been great to see the way Aaron has adjusted to training.
"When you sign a player in January, it's difficult to find someone who is up to speed with the league and up to speed with his match fitness.
"He's an incredible performer at this level, he's beaten some landmarks in the league already and he's got incredible international experience.
"He's fully fit, he's ready to make an impact and he's ready to be in the squad for the weekend.
"I know there's been a lot said about the pictures. I'll chase the photographer. I wasn't happy with that at all."
Everton face Liverpool in the Merseyside derby on Saturday and it remains to be seen who will be smiling after that one.
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