Before including figures, make sure the followings:
Export all images to PDF format. Converting image files (e.g., PNG) to PDF does not render well; you must export the vectorized images to PDF.
Crop white margins around the image. If you use Mac OS or Linux, you can simply type the following command in a terminal, which will crop image.pdf and save it to image-crop.pdf:
$pdfcropimage.pdfimage-crop.pdf
Figures in Column
Use the following template to include figures in column: