Many in the audience assume lossy compression results in significantly inferior display quality for the image. I warn everyone that I am about to move ahead to a second image – one that’s compressed using a lossy algorithm. When I talk at meetups, the way I introduce image compression to my audiences is to show a screenshot I took while building the presentation. This post will cover the impact of compressing images on Page Load Time and I’ll even prove that impact with some tests towards the bottom. One of my favorites is also one of the most impactful, and it happens to be incredibly easy to do: Lossy Image Compression. In my presentations I cover some easy ways to increase the performance of a website. When the workflow is finished, you will find these files in the output folder:Īre you missing an icon size? Just edit the workflow to fit your needs.A big part of my role as Technical Evangelist at Yottaa is to speak at Meetup groups about web performance. You will be prompted to select a destination folder.You will be prompted to select the 1024x1024 PNG source image.Launch the workflow in Automator and Run it.I have set up this Automator workflow to create all icon images. Well, yes, but it gets better: Use Automator ! But can't this be automated with AppleScript? Starting off with a 1024 x 1024 pixels source image (in PNG format), one would have to scale it multiple times in an image editing tool, to export it into all the sizes. The trouble is, how to create the icons, again, and again. If your icons are more complex, adjust the $colour variable as needed.įor iOS development, it is necessary to provide a set of app icons of different sizes, all the way from a high-resolution icon for the AppStore to a tiny icon that will be used in Spotlight search results. Once installed in /Applications, the script will pick it up.įor my simple icons, I can get away with just 256 colours. work/export/AppIcon.pngįinally, I can recommend the use of ImageAlpha, which will optimize your images and reduce the colours. It creates the scaled images in the same directory: $ resizeAppIcons. The script requires a 1024 x 1024 pixel PNG image as input. line to use the image sizes that you need. $pngquant -f $colours -o "$outfile" "$outfile"įeel free to adjust the for width in. # Use exec in ImageAlpha to reduce colours and size. Sips -Z $width "$img" -out "$outfile" $gt /dev/null Size=( $(sips -g pixelWidth -g pixelHeight "$img" | grep -o '*$') ) # Get the current image size: ( width height ) Pngquant=/Applications/ImageAlpha.app/Contents/MacOS/pngquantĪrgs=$(getopt h: *) # do not use to work with 'set' below.Įcho "USAGE: $(basename $0) "Įcho "Warning: ImageAlpha.app is not installed" in a directory listed in your $path variable): #!/bin/sh With some tips from this post, I have now set up the following script, saved in a file like ~/bin/resizeAppIcons, (i.e. Its functionality can also be used through the "Image Events" AppleScript suite. This tool is used to query or modify raster image files and ColorSync ICC profiles. Sips - scriptable image processing system. You can check if it is installed on your machine using: $ which sips I don't know how long it has been there, but it turns out macOS contains a command-line utility to convert images: sips (scriptable image processing system). The preview image can be removed, but it adds another manual hack that is required.īecause of these shortfalls, I became increasingly reluctant to use it and found myself resizing images manually again. When saved, the workflow document contains a preview image which blows up the file to about 1 GB. The workflow document is not easily edited, at least not on a slow machine like mine While that has worked well, it had potential for improvement: In a previous post, I described an Automator workflow to rescale iOS app icons.
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