This is a profile view of a baby iguana. There are several clues to tell that this is a baby iguana and not a gecko. First, if you click on the photo and enlarge the view of his its eyeball, you can see that its pupil is round, not a vertical pupil. Because most geckos are nocturnal, vertical pupils let more light in to their eyes.
Another clue is that this photo was taken in the daytime (in Rincon de la Vieja National Park) and iguanas are diurnal. Also, juvenile iguanas have alternating dark and light bands on their tails, which can be seen in this photo. Most, but not all, geckos have pads on their feet, not claws like this iguana. Tomorrow I will post a photo of a gecko that clearly shows the pads on its feet.
On June 14, I posted a photo of an adult iguana. I think you will agree that iguanas look a lot better as babies than adults.
On June 27, I posted a photo of a baby iguana from the front, which you may want to take a look at to complement the above profile photo.