{"action":"opened","issue":{"url":"https://api.github.com/repos/RealFaviconGenerator/realfavicongenerator/issues/157","labels_url":"https://api.github.com/repos/RealFaviconGenerator/realfavicongenerator/issues/157/labels{/name}","comments_url":"https://api.github.com/repos/RealFaviconGenerator/realfavicongenerator/issues/157/comments","events_url":"https://api.github.com/repos/RealFaviconGenerator/realfavicongenerator/issues/157/events","html_url":"https://github.com/RealFaviconGenerator/realfavicongenerator/issues/157","id":70706665,"number":157,"title":"PNG files are created with 48/64 bit depth, not 24/32 - results in increased file size, potential incompatibility/standards breach","user":{"login":"Strobey","id":12099861,"avatar_url":"https://avatars.githubusercontent.com/u/12099861?v=3","gravatar_id":"","url":"https://api.github.com/users/Strobey","html_url":"https://github.com/Strobey","followers_url":"https://api.github.com/users/Strobey/followers","following_url":"https://api.github.com/users/Strobey/following{/other_user}","gists_url":"https://api.github.com/users/Strobey/gists{/gist_id}","starred_url":"https://api.github.com/users/Strobey/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/Strobey/subscriptions","organizations_url":"https://api.github.com/users/Strobey/orgs","repos_url":"https://api.github.com/users/Strobey/repos","events_url":"https://api.github.com/users/Strobey/events{/privacy}","received_events_url":"https://api.github.com/users/Strobey/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":0,"created_at":"2015-04-24T14:37:17Z","updated_at":"2015-04-24T14:37:17Z","closed_at":null,"body":"I noticed that some of the PNG files RFB creates, specifically the android-chrome\\*.png and apple-touch\\*.png have 48 or 64 bpp rather than the expected 24 or 32.\r\n\r\nThis isn't always the case, it seems to primarily happen to those created with the \"Add a solid, plain background....\" feature, but there might be other settings that do it.\r\n\r\nThis has a few problems:\r\n- Firstly, the __filesize__ - eg. android-chrome-192x192.png (48bpp) was __34.41KB__. When I re-saved this as a 24bpp PNG the filesize dropped to __15.28KB__ - that's over __55% smaller__!\r\nSimilarly, the apple-touch-icon-precomposed.png (64bpp) was __28.60KB__, when re saved as 32bpp it was __14.44KB__, about __half the size__.\r\n\r\n- Secondly a possible breach of standards - according to the w3C (http://www.w3.org/2005/10/howto-favicon) - \"the format for the image you have chosen __must__ be 16x16 pixels or 32x32 pixels, using either __8-bit or 24-bit colors.__   \"\r\nAlso the Apple documentation (https://developer.apple.com/library/ios/documentation/UserExperience/Conceptual/MobileHIG/IconMatrix.html#//apple_ref/doc/uid/TP40006556-CH27-SW2) suggests that the bit depth should be 24/32bits.\r\n\"The standard bit depth for icons and images is __24 bits__—that is, 8 bits each for red, green, and blue—plus an 8-bit alpha channel, for a total of __32 bits.__ \"\r\n(emphasis mine)\r\n\r\n- Thirdly, this could potentially cause compatibility problems with devices that aren't expecting this format or that perhaps have an old or buggy PNG library. Given the targets affected by those particular PNG's, this is unlikely, but it's a possibility. \r\n\r\nThanks."}}