Train classifier on synthetic images to recognise real images
Neural networks require a lot of data for training. This is one of their largest drawbacks, and is very hard to get around this.

Using artificial data is not a solution. We don't really understand what the network is learning and we can't tell if it learned anything that is particular to the synthetic images.

What you can do is to use some sort of data augmentation. Rotate, scale, translate your images many times, and create a larger dataset.

Since it's such a small dataset, and if more data is really not possible to obtain, you should consider other approaches to help the classification. Either manually design some features to help a bit the classifier or do the classification with more traditional methods.