The green tomato on the left doesn't look like it was eaten. It could be the tomato just split, which sometimes happens with variable watering.
The red tomato was definitely eaten by something. The hole is pretty big so I'm thinking not insect or worm, but maybe a bird (because it is so hollowed out -- squirrels and things like that that come along and take a bite, don't usually leave it so hollow)?? Not sure.
The Red tomato looks like a bird was thirsty. When it is hot, dry and has not rained for a while birds will peck your tomatoes to get a drink. Put a bird bath in your yard or garden it will stop bird damage to tomatoes. Birds like water better than tomato juice.
I have come out to the same problem almost everyday this week. I have lost at least 8 tomatoes. our plants are maybe 10 feet from our pond so I think the birds cant resist those bright orbs. we put up a net today to test our theory of birds but I hope the insects can still polinate them.
Climbing cutworms also make similar damage. At dawn/dusk? Or on overcast days, they may still be sleeping off their full bellies curled inside the hollow or making their way down the vine to hide for the day and be in the vicinity of the damaged fruit.
It looks like what happened to my tomatoes last year. It was tomato hornworms, a black and white striped caterpillar. I planted marigolds in my garden this year, and I have had no problems. Bugs don't like marigolds, and will avoid gardens with them. I haven't had to use my organic pesticide at all since the marigolds started blooming.
tomato hornworms are mostly green, blend in with the plant they are on very well, though they do have a little bit of striping which helps with the camoflage effect. Is this what you are talking about?
Your left green tomato picture is due to irregular watering. Cracks appear when the soil drys out. You could improve your fruits by keeping an organic covering at the soil base around your plants.
Your right red tomato is the result of the same soil conditions as the first. The lack of water when the fruit is starting to form, if there are round brown or greenish black patches also seen on other fruits. I see a little yellowing on the outer part of your tomato, as well as a crack. Remove these damanged fruits and continue to water the plants.