Few questions about databases

Hi
I'm doing a simple app which have to display text and pictures.
I want to store this pictures and text in a online database (so it can be updated easily), but the app should read from a local database. So this local db should fetch from the online one when there is changes. But there is few things i don't understand because of my low dev skills.

1. Should i store pictures directly in the db? I know it's not the best solution, but there won't be a lot of pictures and not big sized. If not, how to do then?

2. How can i handle all this online db / local db / app cycle? If there is existing samples it will be welcome.
   Im my mind it works like: at launching of the app, a webservice is used to fill the local db from online db if content have changed, then the app display content from local db. If no changes, no fetching from online db.

3. Online db = Mysql, local db = sqlite?

4. To store local settings like notifications schedulle, theme selection, should i put them in local db or there is another solution?

But maybe i'm thinking wrong way about how to make it work...

Found some topics about PCLStorage, it may do the trick?

Thanks for your help