How to restore photos on computer which are deleted accidently?

There are, but unfortunately those need to be installed before you deleted the photos.
If you deleted photos just by pressing “Delete”, those should be in the recycle bin.
However, if you deleted them by pressing “Shift + Delete”, then those are permanently deleted and cannot be restored back.

Edit: You may find on google; here are some:
EASEUS
UndeletePlus

There is software that you can purchase that can retrieve anything deleted from the operating system. Basically, when you delete information from the computer the information is not really gone. It still remains resident on the hard disk until it is overriden by new information. Look online for software that will recover deleted files from the computer and there are lots to choose from. Of course if its been a long time or if you cannot retrieve the files through conventional means you may have to take the computer to a professional data retrieval company which will extract them from the surface using data forensic technology.

Maybe you could do a system restore. Where you restore your computer back to a past point in time and undoes everything you do after that certain time, so you should get your photos back.

You should refrain from using the computer as there will be the likelihood of writing data on the sapce where the deleted file is located., and when that happens, its bye-bye to your pictures . . .

You should take out the HardDrive, attach a USB adapter and connect to a PC with a data recovery software. Check on craigslist for people who provide computers services in yourt area. ask for references before you have anyone work on your PC.

System Restore will not restore non-system files, and picture files are non-system files.

Recuva for Windows has worked for me.
http://www.piriform.com/recuva

Assuming you have Windows (if not let us know)...
Recapping what others wrote
—Try the recycle bin first
—Check to see if “Windows System Restore“http://en.wikipedia.org/wiki/System_Restore is on
—If those do not work, try Recuva (or a similar program)
—It is MUCH better if you can run the prorgram from another computer (Everything you do on your machine has a chance of overwriting the deleted files)

@njnyjobs I forgot about your last point.

System Restore for Vista and Windows 7 can back up picture files.
System Restore for Windows XP cannot.

You can’t restore them if you deleted them permanently and if you don’t have that program already installed on your pc. But first look into recycle bin and maybe you’ll find them there.

Pray.