Resizing crops before saving.

[hoominchu]

Resolves #3467

To avoid saving images of different resolutions based on the user's browser zoom level, we are resizing the images on the server side right before saving it. This way we will have uniform size for all the crops saved.

Testing instructions

1. Change the browser zoom to more than 100%. Place a label. Make sure that the crop saved is of size 1440x960.
2. Change the browser zoom to less than 100%. Place a label. Make sure that the crop saved is of size 1440x960.

Things to check before submitting the PR

• I've written a descriptive PR title.
• I've added/updated comments for large or confusing blocks of code.

[misaugstad]

I changed from SCALE_DEFAULT to SCALE_SMOOTH and fixed some indentation. Thanks @hoominchu !