When viewing the trip itself, you can select Notes from the … action menu and add a Note for later when you run the Post Trip Assistant. The note can be General, Task Answer or Deviation reflecting something different than expected.These notes support uploading a picture to accompany them along with your note text.
At the level of an individual cache, you can also have Notes. In general, you can note an action like Found, DNF, Skipped and others. You can check off that you took a picture, that you want to favorite it, or that it needs maintenance. These will later guide you in writing a log for the cache. When done, tap Save or Save and upload (if you have data signal).
If you happen to be doing a virtual or an Earth Cache, the … menu offers a chance to upload a picture you can use in supplying task answers later in the Post Trip Assistant.