When multiple classes with the same name are downloaded, they are merged into one folder

For example, the following classes share the same name and thus all get downloaded to the same folder named 'cap'.

```
n02954340, cap
n02954938, cap
n02955065, cap
```

I suggest adding a folder name suffix such as `cap_n02954340`. This way the folder can still be sorted alphabetically and images don't get mixed together.