Photoshop user? Why not RealFaviconGenerator?

Photoshop is a great tool. Use it and you can expect your pictures to be just perfect. Well, almost perfect.

Let’s see what Apple got when they created their own Touch icon:

$ wget -o apple-icon.png http://www.apple.com/apple-touch-icon.png
$ ls -l
-rw-rw-r-- 1 philippe philippe 4506 Aug 12  2015 apple-icon.png

4506 bytes for a Touch icon? Sounds legit. Now let’s have a look to its metadata:

$ exiftool apple-icon.png
ExifTool Version Number         : 9.46
File Name                       : apple-icon.png
Directory                       : .
File Size                       : 4.4 kB
File Modification Date/Time     : 2015:08:12 19:51:29+02:00
File Access Date/Time           : 2016:05:17 17:00:31+02:00
File Inode Change Date/Time     : 2016:05:17 17:00:31+02:00
File Permissions                : rw-rw-r--
File Type                       : PNG
MIME Type                       : image/png
Image Width                     : 152
Image Height                    : 152
Bit Depth                       : 8
Color Type                      : RGB
Compression                     : Deflate/Inflate
Filter                          : Adaptive
Interlace                       : Adam7 Interlace
Software                        : Adobe ImageReady
XMP Toolkit                     : Adobe XMP Core 5.5-c021 79.155772, 2014/01/13-19:44:00
Original Document ID            : xmp.did:15d8a979-1097-4474-accc-90fc2b02fc58
Document ID                     : xmp.did:25F46708355311E580E8DA1A4BE6CE82
Instance ID                     : xmp.iid:25F46707355311E580E8DA1A4BE6CE82
Creator Tool                    : Adobe Photoshop CC 2014 (Macintosh)
Derived From Instance ID        : xmp.iid:d4dcd418-cd4f-4a8e-a9eb-670e43ff2ee8
Derived From Document ID        : adobe:docid:photoshop:3a0c5b59-7dbd-1178-bb27-91c7aa683e3f
Image Size                      : 152x152

Apparently, this icon was generated by Photoshop.

These are a lot of information… What happens if we remove all EXIF data?

$ exiftool -all= -o apple-icon-no-exif.png apple-icon.png
$ ls -l
-rw-rw-r-- 1 philippe philippe 3555 May 17 17:04 apple-icon-no-exif.png
-rw-rw-r-- 1 philippe philippe 4506 Aug 12  2015 apple-icon.png

We’ve just decreased the size of the Apple Touch icon by more than 20% just by removing the metadata!

Now let’s do the same of, say, the Alphabet Touch icon, wisely generated by RealFaviconGenerator:

$ wget -O alphabet-icon.png https://abc.xyz/apple-touch-icon-152x152.png
$ exiftool -all= -o alphabet-icon-no-exif.png alphabet-icon.png
$ ls -l
-rw-rw-r-- 1 philippe philippe 3714 May 17 17:09 alphabet-icon-no-exif.png
-rw-rw-r-- 1 philippe philippe 3714 Apr 21 05:17 alphabet-icon.png

(yep, we took the 152×152 version, because this is the size of Apple’s Touch icon)

Now, the image is 3.7KB, with or without EXIF, simply because RFG does not produce verbose metadata.

Okay, it’s not entirely Photoshop’s fault. It probably has options to not be that verbose. Plus you’re responsible of post-processing your assets before deploying them. But if Apple did the mistake, others probably made it too. But at least not RFG users.

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