![]() #!/bin/bashadds a strip of transparency to png images so twitterwon't convert them to jpg and make them look like crap./png2twitter something.pngimg="$.png" instead of having that mv command. I'm going to put code tags around it in the hope that your blog will use those for formatting. I wrote a script a while ago for when I want to post png images to Twitter. One of the advantages of hosting your own content is that you - the user - get to choose what is an appropriate trade-off between quality and filesize. That looks nasty! There appears to be no way to download the original. In my experiments, Facebook compressed the transparent PNG to a 71% quality JPG. The format uses compression, but the files can. They will let you see the original PNG once you click through. PNG is useful because its the only widely supported format that can store partially transparent images. When you save an image as a JPG, the algorithm deletes some data to reduce the file size. ![]() Lossy compression, as the name suggests, involves some degree of data loss, which is what a JPG does. PNG, is the compression method they use specifically, lossy (JPG) and lossless (PNG) compression. LinkedIn displays an 85% quality JPG in the preview. One of the major talking points when looking at JPG vs. If you can't bear to have a "missing" pixel - you can set a single pixel's opacity to 90%. The only way to avoid it is to make sure at least one pixel is transparent. By default, Twitter compresses your PNGs to JPG. JPEG compression is terrible for solid blocks of colour (especially red) next to fine details. Using GIMP - or any other photo editing tool - you can crop out a pixel from the image: When Twitter sees even a single transparent pixel, it refuses to convert the original image and keeps it as a PNG. PNGs have an interesting property that JPG images don't - they can be transparent. That's not sufficient for images like this. Yuck! Look at the grimy artefacts surrounding the text! By default, the image quality that most websites choose is 85%. If you upload it to Twitter, it will automatically be compressed to a low quality JPG. ![]() ![]() Solid red - with some fine detail in white: Here's an example - this detail of a logo from my former employers, Vodafone. This can have negative consequences for usability and image quality. Let's talk image compression! Services like Twitter will often apply aggressive levels of compression in order to reduce their storage space and decrease download times. Some of the techniques in this blog post may be out of date. Update for 2019! Twitter have changed how they compress images. ![]()
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