Convert Image

HEIC is why most people end up here

Since iOS 11, an iPhone camera writes HEIC by default. It is a HEIF container holding an image compressed with HEVC — the same family of compression used for video — and at matched visual quality it is roughly half the size of a JPEG. That is genuinely better engineering, and it is also why the format is such a nuisance in practice.

Outside the Apple ecosystem support is patchy. Windows needs an extra codec package before Explorer will even show a thumbnail, older Android versions cannot open it at all, plenty of upload forms reject it by extension, and a surprising number of internal systems — expense portals, HR document uploads, ticketing attachments — simply fail with no useful error. You end up with a phone full of photos that the one system you need cannot read.

Converting to JPG fixes all of that. The cost is real and worth stating: HEIC can carry depth information for portrait-mode blur, and it can store 10-bit colour for HDR. Neither survives the trip to JPEG, which is 8-bit and flat. You are also converting compressed data to compressed data, so there is one generation of quality loss on top of whatever the phone already applied. If you still have the original, keep it — that is your archive; the JPG is the copy you send.

Which of the three formats to actually pick

JPEG is the universal one. Twenty-five years old, lossy, no transparency, and readable by literally everything including scanners, printers and fax-adjacent hospital systems. When in doubt and the destination is unknown, this is the safe answer.

PNG is lossless with an alpha channel. For photographs it is a poor choice — often several times the size of a JPEG with no visible advantage. For screenshots, logos, charts, UI mockups and anything containing text or flat colour it is the correct choice, because lossy compression is exactly wrong for sharp edges and large uniform areas. A PNG screenshot stays crisp at any size; the same screenshot saved as JPEG grows fringing around every letter.

WebP does both jobs: it has a lossy mode that is typically 25–35% smaller than JPEG at similar quality, a lossless mode that beats PNG, and it supports transparency in either. Every current browser reads it. What it is not is universal outside the browser — older Photoshop releases, some content management systems, plenty of older Android apps and most print workflows will refuse it. The rule that works: files going to a person or a website you control can be WebP, files going into someone else’s uploader or to a printer should be JPG or PNG.

Transparency is where conversion actually breaks

This is the single most common way a conversion goes wrong, and the failure is usually blamed on the tool rather than the format. JPEG has no alpha channel — there is nowhere in the file to record “this pixel is see-through.” So every transparent pixel has to become some actual colour, and if nothing chooses one, encoders fall back to black. That is why a logo with a transparent background comes out sitting on a black rectangle.

Here the fill colour is explicit and defaults to white, and the field only appears when you have selected JPG, so a PNG or WebP conversion never touches your transparency — those formats keep it intact. If you are converting a logo and want it placed on a specific page colour, set that colour here rather than fixing it later in an editor.

Two related misunderstandings worth clearing up. Converting a JPEG to PNG does not restore any of the detail a JPEG threw away — it faithfully preserves the damage and makes the file bigger. And converting a small blurry JPEG to PNG does not make it sharper. Neither direction adds information; the only thing that changes is the container and, for lossy targets, the amount of further loss.

What conversion does not do

Being clear about the boundaries saves you from a wrong result you only notice later.

• It does not resize. Pixel dimensions come out exactly as they went in, and the result list prints them so you can confirm that. Shrinking is a separate job with its own tool.
• It does not improve quality. A heavily compressed source stays heavily compressed, and re-encoding it into a lossy target adds another generation on top. Convert once, from the best original you have.
• It does not preserve animation. An animated GIF or animated WebP is decoded as a still frame, so what you get back is the first frame only. The interface flags this on the file as soon as you add it, because a silently frozen animation is the kind of mistake you notice a week later.
• It does not produce CMYK or TIFF. Professional print workflows want CMYK colour and often TIFF; browsers work in RGB and this tool outputs RGB only. For a commercial print job, do the final conversion in the print shop’s own toolchain.
• It does not guarantee anonymity. Converting a phone photo does strip the EXIF block including GPS coordinates, since the image is redrawn to canvas, but if your goal is to publish something nobody can trace, check the result before you post it.

Practical recipes

A few combinations that come up constantly, with the settings that solve them.

• iPhone photos for a form that rejects HEIC: HEIC → JPG at quality 85. If the form also has a size limit, compress afterwards rather than lowering the quality further.
• A screenshot for documentation or a bug report: keep it PNG. Converting a screenshot to JPG is the most common way people accidentally make text unreadable.
• A logo for a website: PNG or WebP if it needs a transparent background, and check the WebP support matrix of whatever you are pasting it into.
• A photo for a chat app: JPG at quality 80. Most messaging apps recompress anything you send anyway, so sending a maximum-quality file mostly wastes upload time.
• Something for a printer or a government portal: JPG or PNG. Both accept those; WebP is the one that will bounce.