Images are resized automatically during the upload process this allows you take all your high res images and start uploading. However if you like you can batch process them before hand for a much faster upload. If you resize the images, we recommend these settings:
You can batch resize the images to 3500 pixels on the longest side (aspect ratio maintained) in Adobe Photoshop or similar software before upload. The uploader will then skip the resizing during upload and simply upload the file directly.
You can view our batch resize guide at the link below: