PIL cannot write mode F to jpeg

Question

I am taking a jpg image and using numpy's fft2 to create/save a new image. However it throws this error

"IOError: cannot write mode F as JPEG"  

Is there an issue with CMYK and JPEG files in PIL???

p = Image.open('kibera.jpg') bw_p = p.convert('L') array_p = numpy.asarray(bw_p) fft_p = abs(numpy.fft.rfft2(array_p)) new_p = Image.fromarray(fft_p) new_p.save('kibera0.jpg') new_p.histogram() 

Answer 1

Semente's answer is right for color images For grayscale images you can use below:-

new_p = Image.fromarray(fft_p) new_p = new_p.convert("L") 

If you use new_p = new_p.convert('RGB') for a grayscale image then the image will still have 24 bit depth instead of 8 bit and would occupy thrice the size on hard disk and it wont be a true grayscale image.

Answer 2

Try convert the image to RGB:

... new_p = Image.fromarray(fft_p) if new_p.mode != 'RGB':     new_p = new_p.convert('RGB') ...