Any application to apply a file extension for group of files

I have about 300 to 400 pictures in a folder which are considered to be as documents by my windows operating system. The pictures are in .png format I had to get Information on every one of them and need to relate them as documents with Preview, and that is working fine. But the Finder still does not identify them as pictures and because of that does not affect a preview in icon view. So I am looking for the application that will permit me drag entire documents into it and have it mass apply as .png file extension but still no help from anybody. So anyone has done it please provide me with name of application and processor to perform that it will be great help.

You can perform steps that might solve your problem using Automator application:

• You need to first pull all the files in question into Automator. There in Files and Folder category you need to choose Rename Finder Items.
• Now you need to pull it below your files in the right window and choose "Add Text" in the pop-up menu that will appear.
• Now just add the extension as ".png" after the picture name and click on run.

You can perform this as:

1. For doing this you need to go in My Computer and then there go to Tools and in Folder Options.
2. Now move to the View tab and roll down till you find the alternative “Hide extensions for known file types“. You have to uncheck it.
3. And if the files which you have to change the extension have no extension this step can be avoided, now you need to right-click on your file and select Rename option.
4. Now shift to the end of the name and type in .png or what extension you want to give. Clearly the file has to have formerly been from that program that you are altering the file extension too.

For renaming file extension of group of file you can use the application Extension Renamer, it is an easy to use application. Best think about it is that it is freeware program you can download it after which it will take no time to change file extensions.

• Firstly tick Select Directory and select the folder that holds all of the files for that you want to change the extension. You also can have the alternative of counting subdirectories, then you search for files with particular file extensions that you want to change.
• Now you can enter in your extension .png that you want to place. Click on Search and the files that will be altered illustrate up in the left container. Once all is done click on ok after which all of your files in the folder will have the replaced extensions.

You can perform the change in the file extension for your file that are not recognized by your system.The applications which you can use such as
NameWiz :This will permit you rename files, folders and sub-folders in group with that it is also a superior file renaming utility. Some of the files are nearly unfeasible to be rename but NameWiz can be more extended using plugins using which you can rename everything there is no restrictions. Change or add file extensions, file collection by position, indicate capitalization rules, sorting by name, size, and extension. You can do the various extensions; Rename your files in Numerical, Alphabetical or Alphanumeric whichever you want.

You can have the application named as rjhExtensions is a easy utility that adds a number of helpful functions to the framework menu of Windows Explorer. The utility consists of the extensions and a controller that permits you to control the assignment of the extensions using that you can Rename Files extension as well as allows you to rapidly and simply rename multiple files in numerous folders. It has Encrypt File that allows you to simply encrypt and then decrypt any file using a customized edition of the influential Blowfish encryption algorithm.

Yes there is application RenameWiz with features that include Save and run up to 150 diverse rename commands using system scheduler or generating routine shortcuts. Using this you can Rename number of files or folders by or without recursion. You can "Search and swap" characters anyplace in filenames or folders. Rename file extensions Optionally rename "Read Only or the System Hidden" Files you can eliminate file extensions while numbering them.