Convert an image file to JPEG format by using Adobe Photoshop or the online conversion tool at ConvertImage.net. While ConvertImage.net is free to use, Photoshop is a paid program but offers greater tuning.
To convert an image file to JPEG format using Adobe Photoshop, open the image file you want to convert in Photoshop, click File, and then click Save As. Once the dialog box opens, click JPEG from the drop-down menu, and click Save. Photoshop then asks for a quality rating. The higher the quality, the larger the file size.
Alternatively, click JPG at Convertimage.net, and then click Select Your Image. Navigate to the folder containing the image, select it, and click OK. Click the switch below the file name fieldm and click Convert This Image. Once the conversion completes, ConvertImage.net takes you to another page. Click Download the Image to save the JPG file. Because JPG and JPEG are the same format, you can rename the extension to JPEG, if desired.
The JPEG image format does not have an alpha channel. Therefore, JPEG images cannot display transparency. If you convert a PNG or a GIF image with transparent parts to JPEG, the transparent parts appear black. Because the alpha information is lost during the conversion, converting the JPEG file back to PNG or GIF does not bring the transparency back.
The letter variation of the extension is due to a limitation of older Windows versions. Newer versions of Windows support four characters as file extensions, including JPEG.