Please connect the phone to the computer and find the DCIM folder on the external/internal storage unless you used a transferring application that was set up to delete the files after copying. If the process succeeded then you can copy back the files to your phone.
If the pictures were stored on the external device (microSD card) then you can use R-studio to recover your photos. R-studio is an application which is used for files and folder recovery.
Download and install the application in trial mode, connect the card to the computer through a card reader then select the partition of the card and use SCAN to search for your files. You can also define a scanning pattern so that the application will scan only for image files.