This bug would have a lot in common with bug 151369, so I suggest you go
for that first, if it hasn't already been implemented

The idea in this feature is to add a "favorites" icon to the home page,
which allows the user to store searches he uses a lot

Here are some implementation suggestions

Step 1 + 2: Add a new page to the browser
-----------------------------------------
These two steps are similar to step 1+2 in bug 151369, and you may actually
be able to share some code with that.

Step 3: Saving the current location as a favorites
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I suggest you add an entry to the edit menu maybe called "add to
favorites". read comment #1 in bug 193989 for details on adding something
to the menu. When you have the info added to the menu, you would need to
actually save, the current search into the database. You can get your hand
on the current search using BrowserWidget::currentContext(). In bug 151369
it was optional to serialize the ImageSearchInfo data structure - this is
indeed required for this bug, so you can save it to the DB.

You would also need to add appropriate methods to the DB/ImageDB.h
interface and to the XMLDB and SQLDB subclasses (you may wish to just
create a stub for the SQLDB in the first place, and add a bug asking to
implement this).

When adding favorites, I also suggest you offer the user to type a name for
the favorites.

Step 4: Deleting favorites
--------------------------
A final feature is to delete a favorites again. In the browser page showing
the favorites. I suggest that you add a context menu for deleting the
favorites. I'm not entirely sure how you do that, but ask me on IRC and
I'll help you in the right direction. I guess you would need to set up the
context menu on the BrowserWidget class, and delegate the result to the
BrowserPage subclass.

Step 5: Optionally
------------------
An addition feature would be to allow to associate an image with the
favorites item.

Step 6: Look at bug #145631
---------------------------
Once you have added the context menu above, you may accidentally have fixed
bug #145631, please double check that.