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How do you convert a png file to JPEG?
For a single task, no special requirements on the image quality, you can use even MS Paint. Open the file and save as jpeg. The same works with other image editiong programs (…gimp, photoshop, irfanview...). They allow for better control over the results, because they allow to select the parameters of the jpeg algorithm as well. Doing the same over and over is painfull with these tools (some degree of batch processing is provided, but this is not much). You should look to an image converter. For example AZImage - see related links. (MORE)