There are three main reasons why images may look pixelated in Photoshop: because of the way pixels are created when a photo is processed, because of the way Photoshop handles transparency, and because of how Photoshop handles color.
There are a few ways to resize an image in Photoshop without stretching it. You can use the zoom tool to increase or decrease the size of the image, or you can use the selection tool to select a specific area of the image and drag it around to change its size.
There are a few ways to install PNG files:
Use a program such as Adobe Photoshop or Illustrator.
Use a web browser and navigate to the file’s location (for example, http://www.example.com/file.png).
Use an FTP client to transfer the file to your computer.