Add ability to attach images with captions to entries

```
"A picture is worth a thousand words."  ThotKeeper users would benefit from the 
ability to attach photos with captions to the their entries.  This could be 
introduced in phases, from simple attachment and storage to more elegant 
display.
```

Original issue reported on code.google.com by `cmpilato` on 21 Sep 2012 at 2:34
