If you work with images for the web, it can be a challenge to reduce file size. Each time we reduce file size, we reduce our bandwidth and our sites load faster. TinyPNG was created for this purpose. It works with both .png and .jpg files.
I took 11 sample .png and .jpg files from my download folder and ran them through TinyPNG. It saved 83% file size and took less than a minute.
TinyPNG has great developer API to automatically shrink your files. If you use Amazon S3, the API can automatically upload the files to your S3 bucket.
There are other alternatives out there. The one I've used the most is a Windows desktop app called PNGGauntlet. I've found it to be slow and not provide the kind of results that I've seen in TinyPNG.
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If you're using any images on your website, please take the time to compress them for all of us using our phones to load your site.