Add option to raise limit

[Firestar-Reimu]

#46

I have a 14000x19000 image which I would like to resize, but I run into:

'PIL.Image.DecompressionBombError' when resizing large image

I google it and find:

https://stackoverflow.com/questions/51152059/pillow-in-python-wont-let-me-open-image-exceeds-limit

but it needs to change the source code

maybe it's good to add an option to raise the limit