Is there any way to retrieve deleted images from a

I'm sure you may have heard that when you delete a file from a computer, it is never "truly deleted." That statement, however, is only partly true. The files do not get deleted after, only the space that they occupy on the disk get prepared to be written over. When you reformatted the memory card in your camera, it did exactly that, and only prepared your pictures to be written over.

SO, the first thing you have to do after format is to not save any more pictures onto that memory card or you risk writing over the pictures that you are trying to recover!

Got that far? Now you need to choose the appropriate photo recovery software. There are a TON of different programs but some are better than others. I actually recommend a program called 001 Picture Recovery because they have an option that is designed for recovering photos from FORMATTED memory cards, not only deleted or corrupted photos. You can download this software here: http://www.001-software.com/picture-recovery/

Lastly, if the program does not recognize your SD Card as a drive when you are plugging the camera directly into the computer, you may need to directly plug your card into a card reader. Make sure that the card reader has the capabilities to handle your memory card though. Many older card readers can only handle cards up to 2GB, so if your card is bigger than that, you need a newer card reader.

I hope that helps, and that you get your pictures back like I did!

First of all, do not save any new file to camera's memory card.

Take out memory card, and connect it to computer using a card reader. You should see memory card shown as a drive letter (like H:) in Windows Explorer.
Download this photo recovery software
http://www.asoftech.com/apr/
Install and open the photo recovery software, select the memory card, and click 'Start' button.

If you are using a memory card, take no more pics until you've recovered the photos, take the card out of the camera. This is to reduce the chance of you overwriting some of your "lost" photos. There are many good freeware photo recovery software options that are available to help you recover your photos. This blog article reviews and outlines several of the better ones.

Yes, there are ways for you to retrieve these deleted photos back from this camera memory card as long as you've not overwritten them with anything new.
In fact, after the deleting process, the deleted photos on a camera memory card are not actually wiped out as we normally think. They are still stored on this memory card and only become invisible. But, they cannot be there forever. They can be rewritten by anything new on the same memory card.
So, you should take care.
Here are my steps for you to get back your deleted photos:
Step1. Stop using this camera in case that any new file would rewrite your original data.
Step2. Insert this camera to your computer and prepare to restore your data.
Step3. Download a deleted photo recovery freeware to your computer and start to retrieve all your deleted contents back:
http://blog4mark.blogspot.com/2012/12/photo-recovery-after-delete.html
In fact, this freeware has ever successfully saved all the inaccessible data of my friend off from his camera. So, I believe it can also work successfully on your camera memory card, too.
Simply read more information of this freeware here:
http://www.freeware-fix.blogspot.com/2013/02/photo-recovery.html
Step4. Save and back up all the restored photos on a different memory card or drive in case of data recovery failure.

Okay ,if your new photo covered the old data then it's hard to recover,and you can try to download the Hodo photo recovery online and use the free trial to scan, if you can scan it you can recover it.
http://www.goshareware.com/resource/canon-photo-recovery.html

If the photos are not overwritten by new data, you can recover deleted photos. Use data recovery software named Card Data Recovery, it can help you recover photos, video, audio and documents from digital camera's memory card.