First, Why? I have renamed most of my images so they begin with 1986 to 2014 or any year that begins with a 19 or 20. I do not want to rename them again and put anther date year at the beginning.
And, I want to Rename all jpgs and gifs that do not begin with 19 nor 20, to the Date and Time created and keep the old file name and extension, too:

Rules: *.jpg;*.gif/19*/20*

/ in this example means “Not if it begins with”.
19* and 20* means “anything following a 19 or 20”.
*.jpg means “any filename with a jpg extension” (AKA a “wildcard”).
The entire rule says “work on any jpg and any gif /not if it begins with 19 and /not if it begins with 20”.

Destination: %YearCreated%%MonthCreated%%DayCreated%-%HourCreated%%MinuteCreated%%SecondCreated% %FileNameExt%

The result would look like this: 20140104-161834 Fruits in a Woven Basket.jpg

Note that even if the original filename was 18 Fruits in a Woven Basket.jpg, the new filename would be 20140104-161834 18 Fruits in a Woven Basket.jpg because 18 is not excluded, only 19 or 20.

Instead an original filename ‘20 Fruits in a Woven Basket.jpg’ would be skipped in the rename task because of the 20. This is the reason why we used /19*/20*.
You must rename it yourself or rename it to remove the 20 and run it through again to get the date and time and then edit to put it back in (obviously if you want to).

Here, I want to Rename (only) all jpgs so they begin with the Date created as YYYYMMDD, dash, dash, Time created as HHMMSS, underscore, and keep the old filename and extension:

Rules: *.jpg

Destination: %YearCreated%%MonthCreated%%DayCreated%--%HourCreated%%MinuteCreated%%SecondCreated%_%FileNameExt%

It would look like this: 201303115--093304_DSC00043.jpg
Notice the double dash between date and time, and underscore after seconds.

Here, I want to Rename (only) all gifs so they begin with the word PICTURE, underscore, Date created as YYYYMMDD, @, Time created as HHMMSS, underscore, and keep the old filename and extension:

Rules: *.gif

Destination: PICTURE_%YearCreated%%MonthCreated%%DayCreated%@%HourCreated%%MinuteCreated%%SecondCreated%_%FileNameExt%

It would look like this: PICTURE_20120704@134522_MVC000024.gif

In this example, I want to Rename (only) all gifs so they begin with the word PICTURE, underscore, Date created as YYYYMMDD, @, Time created as HHMMSS, underscore, Use USER INPUT while looking at picture, space, and keep the old filename and extension:

Rules: *.gif

Destination: PICTURE_%YearCreated%%MonthCreated%%DayCreated%@%HourCreated%%MinuteCreated%%SecondCreated%_%UserInput% %FileNameExt%

It would look like this: PICTURE_20120704@134522_Betty at the Beach MVC000024.gif

The ‘Magic DropIt Word’ %UserInput% pops up a window on screen so the user can input words accurately to include them into the renaming of the image MVC000024. The user in this example typed Betty at the Beach. Looks accurate because the date of the photo is July 4th at 1:45pm.