Batch Resize

Images for Video: Batch Resize

This guide will give you step-by-step instructions on how to resize a batch (group) of images.

Why? A video frame usually has smaller pixel dimensions than a still image. This is because digital stills cameras take images at a high resolution suitable for printing. Video frames are recorded to be displayed on a screen, not printed, and therefore only need to match the screen's resolution.

For example: your image may have pixel dimensions of 3000x2000 or more, whereas a standard definition video frame is only 768x576 (4:3). Even high definition video is only 1920x1080 (16:9). So you can see that your image is much larger than required.

You can leave your images at their original pixel size if you want, and most video software will automatically scale them down to fit the video frame, or allow you to manually scale them. The downside of this is that when you play back your images as video, the computer has to work a lot harder to scale each frame down 'on-the-fly'. This means that playback quality may be lower, performance will be slower and previews/renders will take longer.

The Exception to the Rule: If you want the image to be larger than the video frame, perhaps so that you can animate a zoom or pan on the image, you would not want to resize it to the size of the video frame. In this case, think about how you want to use the image and make sure it is large enough, but not too large.

For example: If you had an image that you were going to use in a standard definition widescreen (16:9) video and you wanted it to fill the frame, then you would resize it to 1024x576 pixels. If you wanted a x2 zoom in on the image, then you would need it to be twice as large as the video frame, i.e. 2048x1152 pixels, otherwise pixelation of the image (blocky look) would occur as you zoomed in (scaled it up).

Guide:

  1. Organise (move) the images you want to resize into a folder.
  2. Open Adobe Bridge and navigate to where your images are saved:
    Bridge.png
  3. Choose Tools > Photoshop > Image Processor. Tip: You can also access this from within Photoshop by choosing File > Scripts > Image Processor.
  4. Enter the following options:
    • Choose Save in Same Location (does not save over originals) or select a folder to move the resized images to.
    • Choose the file type - JPEG is fine for video. Set a quality between 8 (high) to 12 (very high).
    • Tick Resize to Fit and enter the pixel dimensions of the video frame you want the images to fill:
Video Frame Pixel Size
PAL SD 4:3 768x576
PAL SD 16:9 1024x576
Web/TV HD 16:9 1280x720
Full HD 16:9 1920x1080
image_processor.png

5. Click Run to start the Image Processor. It may take a little while if you have a lot of images.

Tips:

  • If you choose Save in Same Location, it does not save over your original images. Instead a new folder is created in that location labelled either JPEG, PSD or TIFF.
  • Resizing the image using this method keeps the proportions the same - it does not stretch the image. Therefore, when you resize to fit a certain video frame size, the image will not fill the frame unless it is the same aspect ratio as the frame. To get an image of a different aspect ratio to fill the frame, you must crop or stretch the image to that aspect ratio.
  • You can use this process to convert between file types without resizing - just leave Resize to Fit unticked.
  • You can easily add copyright info to the image metadata by filling in the Copyright Info field. Press alt+G on the Mac keyboard to create a © symbol, followed by your name (and website address?).
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