OSError: cannot write mode RGBA as JPEG Pillow error [Fix]

# OSError: cannot write mode RGBA as JPEG Pillow error [Fix]

The Pillow "OSError: cannot write mode RGBA as JPEG" occurs when you try to save an image with transparency as jpg.

JPG images don't support transparency, so use the Image.convert() method to convert the image to RGB.

cannot write mode rgba as jpeg

Here is an example of how the error occurs.

main.py

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from PIL import Image

with Image.open("house.png") as im:
    rgb_im = im.convert('RGBA')

    # ⛔️ OSError: cannot write mode RGBA as JPEG
    rgb_im.save('house.jpg')

We called the Image.convert() method with a mode of RGBA.

RGBA stands for red green blue alpha.

Alpha indicates how opaque each pixel is. In other words, alpha specifies the opacity (transparency) of the colors.

The JPG format does not support transparency which causes the error.

One way to solve the error is to call the Image.convert() method with a mode of RGB.

main.py

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from PIL import Image

with Image.open("house.png") as im:
    # ✅ Set the mode to RGB
    rgb_im = im.convert('RGB')

    rgb_im.save('house.jpg')

The code for this article is available on GitHub

If you get the error "OSError: cannot write mode P as JPEG", the solution is the same.

The P mode also has alpha (transparency) and cannot be saved as JPG.

You can use the mode attribute to check the mode of an image.

main.py

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from PIL import Image

with Image.open("house.png") as im:
    print(im.mode) # 👉️ P

    rgb_im = im.convert('RGB')

    print(rgb_im.mode) # 👉️ RGB

    rgb_im.save('house.jpg')

The mode of the .png image is initially P. However, after calling Image.convert() with RGB as an argument, the mode of the stored in the rgb_im variable image is RGB.

You can also use an if statement to check if the mode of the image is RGBA before calling the Image.convert() method.

main.py

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from PIL import Image

with Image.open("house.png") as im:

    if im.mode in ('RGBA', 'P'):
        rgb_im = im.convert('RGB')

        rgb_im.save('house.jpg')
    elif im.mode in ('RGB', 'JPEG'):
        im.save('house123.jpg')

The code for this article is available on GitHub

The RGBA and P modes have alpha (transparency) and as previously stated, JPG images don't support alpha (transparency).

The RGB mode does not have alpha and can be saved as JPG.

The example uses the with open() syntax, however, you could also open the image directly.

main.py

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from PIL import Image

im = Image.open('house.png')

rgb_im = im.convert('RGB')

rgb_im.save('house.jpg')

This can also be shortened to a single line.

main.py

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from PIL import Image

Image.open('house.png').convert('RGB').save('house.jpg')

The Image.convert() method returns a converted copy of the given image.

The JPG format is not capable of saving any transparencies.

If you need to set transparencies, you have to pick a different format.

The GIF and PNG image formats support transparency.

# Saving the image as PNG instead

If you don't necessarily have to store the image as JPG, you could save it as PNG.

main.py

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from PIL import Image

with Image.open("house.png") as im:
    im.save('house-new.png')

The code for this article is available on GitHub

PNG images (and GIFs) support transparency, so you won't run into any issues when storing RGBA images as .png.

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OSError: cannot write mode RGBA as JPEG Pillow error [Fix]