I know that PILLOW can convert an image from say jpg to png using the save method but is there a way to convert the image to another format and just keep it as an Image object without actually saving it as another file?
So I want to convert a user supplied image to common format for working with in the program because certain tools I am using only support png.
jpg and png are just compression techniques for saving an image to a file. An image as an object, is just an array of RGB(or any other colorspace/format used by the library which you used to read the file) values of all the pixels.
So technically, you can use the image object as the common format for working with other tools. But you need to keep in mind about the colorspace which is used by each library. Like, OpenCV considers an image object in BGR format, so you need to convert the image object to this format before you use it in OpenCV.
How to convert an image with PILLOW temporarily?