The latest program (link in my signature to Mars Rover Utilities) for you all to try out please is an Extended Sol to Date Calculator.
It uses the database to find out the exact Sol or date and gives the photoid of the first and last picture taken on that date/Sol.
It also gives links to the mars.rover thumbnail page for the sol. If the sol cannot be found in the database, it calculates it as before and gives a link to the page with all the drop-down boxes so that you can select the appropriate Sol and camera.