I'm trying to paste a png on a jpg. Here is the code:
#!/usr/bin/env python3
from PIL import Image
from PIL import ImageDraw
im = Image.open("existing.jpg")
logo = Image.open("python-32.png")
back = Image.new('RGBA', im.size)
back.paste(im)
poly = Image.new('RGBA', (512,512))
pdraw = ImageDraw.Draw(poly)
pdraw.polygon([(128,128),(384,384),(128,384),(384,128)],
fill=(255,255,255,127),outline=(255,255,255,255))
back.paste(poly, (0,0), mask=poly)
back.paste(logo, (im.size[0]-logo.size[0], im.size[1]-logo.size[1]), mask=logo)
back.show()
When I execute the code above, I can see that a PNG image is shown with a random name like tmpc8rb455z.PNG.
I also try to save it with the format jpg but failed. Meaning that when I add back.save('res.jpg', 'JPEG') and execute it, I get such an error:
Traceback (most recent call last):
File "test.py", line 32, in <module>
back.save('res.jpg', 'JPEG')
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PIL/Image.py", line 1893, in save
save_handler(self, fp, filename)
File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/PIL/JpegImagePlugin.py", line 604, in _save
raise IOError("cannot write mode %s as JPEG" % im.mode)
OSError: cannot write mode RGBA as JPEG
Then I try to save it as PNG:
back.save('res.png')
It works but the size of res.png is 5 times larger than existing.jpg. I can not accept such a huge image.