You’ve opened hundreds of PDFs — tax forms, boarding passes, ebooks, contracts — without ever really needing to know what one technically is. That’s kind of the point of the format. But if you’ve ever wondered why a PDF looks identical whether you open it on a Windows laptop, a Mac, or a phone, or … Read more
Someone sends you a company logo, you double-click it, and instead of opening as an image, your computer either shows nothing, opens a wall of code in a text editor, or asks what program should handle it. The file extension is .eps, and unlike a JPEG or PNG, it’s not something most everyday software knows … Read more
That tiny icon sitting next to a page title in a browser tab is called a favicon, and if you’ve ever gone looking for one on your own site or someone else’s, you’ve probably run into a file ending in .ico — a format that looks strangely old-fashioned compared to everything else on the modern … Read more
Every time you save a JPEG, rip an MP3, or zip a folder, you’re making a decision — often without realizing it — about whether it’s okay to permanently throw away some of your data to save space. That decision has a name: lossy vs lossless compression. Nearly every format comparison you’ll read (WebP vs … Read more
Of the “next-generation” image formats that have shown up over the past several years — WebP, AVIF, and JPEG XL — JPEG XL is the one you’ve probably heard the least about, despite arguably having the most technically ambitious goals. There’s a specific, well-documented reason for that: its biggest browser dropped support right as it … Read more
If you’ve optimized images for the web anytime in the past few years, you’ve probably seen “AVIF” mentioned as the format that’s supposedly even better than WebP. It is, in a lot of ways — but “better on paper” and “ready to actually use as your default” are different questions, and the honest answer to … Read more
You’re ripping a CD, exporting a podcast, or just trying to figure out why your iPhone keeps saving voice memos and downloaded music as files that aren’t MP3. AAC and MP3 are both lossy audio formats — both throw away some of the original sound data to shrink file size — but they were built … Read more
If you’ve ever AirDropped, emailed, or uploaded a photo from an iPhone and had it show up as a broken image, an “unsupported file type” error, or a mysterious .heic extension that nothing will open — this is why. Since iOS 11 (2017), iPhones save photos in HEIC by default instead of the JPG format … Read more
You double-click a photo — maybe it came from a website, a WhatsApp forward, or a “Save Image As” — and instead of opening, you get an error, a broken-image icon, or nothing at all. Look at the file extension and it says .webp. That’s a WebP file, and the fact that it isn’t opening … Read more
Every image, video, and audio file you’ve ever opened is stored in some specific format — and the format you choose (or that a device chooses for you by default) has real, practical consequences: whether the file opens where you send it, how large it is, whether it loses quality when compressed, and what it … Read more