JPG or PNG for Your iPhone Photos? The Answer Depends on What You Are Doing With Them.
JPG or PNG for Your iPhone Photos? The Answer Depends on What You Are Doing With Them.
PNG and JPG solve the same problem in fundamentally different ways, and which format you need from an iPhone photo depends on what you are doing with the image afterward.
JPG compresses images by discarding data that human vision is least sensitive to, producing smaller files with a slight quality reduction that accumulates with repeated editing. PNG compresses without discarding anything, producing larger files that survive editing without degradation and preserve every pixel exactly.
For most casual sharing, social media posts, and email, JPG is fine and the smaller size is convenient. For design work, product images, screenshots with text, or any context requiring a transparent background, PNG is the necessary choice. Understanding why requires a brief look at where each format came from and what problem each was built to solve.
PNG did not emerge from a technical roadmap. It emerged from a patent dispute.
On December 28, 1994, Unisys announced that it would begin enforcing its patent on the Lempel-Ziv-Welch compression algorithm, the compression method used in GIF files. LZW had been patented in 1985, and the patent had been largely ignored during the early years of the web because enforcement against free and open-source software seemed unlikely. The 1994 announcement changed that calculation. Companies and developers suddenly faced potential royalty obligations for software that displayed GIF images.
On January 4, 1995, Thomas Boutell posted to the Usenet newsgroup comp.graphics with a proposal for a free alternative format. Oliver Fromme suggested the name PING, which became PNG: a recursive acronym standing for "PNG Is Not GIF." The community converged quickly on design decisions: Deflate compression rather than LZW, 24-bit color rather than GIF's 256-color limit, alpha channel transparency, and support for bit depths from 1 to 16 bits per channel.
The World Wide Web Consortium approved the PNG specification on October 1, 1996. RFC 2083 followed on January 15, 1997. The format solved the patent problem, added transparency that GIF's binary transparency could not match, and provided full-color support. Within a few years, PNG had largely replaced GIF for static images across the web.
The single most important difference between PNG and JPG in practice is transparency support through the alpha channel.
JPG files have no alpha channel. Every pixel in a JPG has three color values: red, green, and blue. The background is always a solid color, typically white when the image was composed against a white background. When you place a JPG on a website or in a design file, a rectangular white or colored box appears around the image. You cannot make parts of the JPG see-through.
PNG supports a fourth channel per pixel: the alpha value. An alpha value of 255 means fully opaque. An alpha value of 0 means fully transparent. Values in between create partial transparency, which is what makes soft edges, shadows, and anti-aliasing around curved or diagonal edges look smooth when composited against any background color.
Product photography is the most common professional context where this distinction matters. A product image shot against a white background, when converted to PNG and then processed to remove the background, produces a PNG with full transparency around the product. This image can be placed on any colored page, any texture, or any other image with clean edges. The same workflow with a JPG source requires re-cutting the edges every time the background changes, because the white background is baked into the pixel data.
Interface and UI screenshots often benefit from PNG for similar reasons. Text on a colored background in a PNG remains crisp with no color bleeding at character edges. JPG compression introduces chromatic artifacts around high-contrast edges, such as black text on white, that are visible at normal viewing sizes.
PNG uses lossless compression. Deflate, the underlying algorithm, is the same compression used in ZIP files and gzip streams. It finds repeating patterns in the data and replaces them with shorter references. Every pixel value is preserved exactly, and decompressing the file returns the original data without any change.
JPG uses lossy compression. The JPEG algorithm converts image data from spatial representation (pixels) to frequency representation using Discrete Cosine Transform, then discards high-frequency components that human vision is least sensitive to, then applies Huffman coding to the result. The discarded data cannot be recovered. Opening a JPG file and re-saving it at the same quality setting applies the compression cycle again, discarding additional data and introducing additional artifacts.
For a single save cycle, the quality difference is invisible at quality settings of 85 or higher out of 100. For images that will be edited across multiple sessions and saved multiple times, the accumulation becomes visible. Design assets, images used in templates, photos used repeatedly in different projects, and any image that serves as a source file for further work benefit from being stored as PNG to avoid progressive quality loss.
The tradeoff is file size. A PNG file of a typical photograph is substantially larger than a JPG of the same image. For full-frame photographs with complex detail and gradients, PNG files can be three to five times larger than equivalent JPG files at quality 85. For images with large areas of flat color, simpler patterns, and fewer gradients, the size difference is smaller because PNG compression handles repetitive data efficiently.
HEIC from an iPhone camera contains photographs with full photographic complexity: gradients, fine texture, varied lighting. This type of content compresses efficiently with JPG and shows minimal quality loss in single conversion at high quality settings. JPG is the right conversion target when:
The image will be uploaded to social media, shared by email, embedded in a web page, or submitted to a service that accepts standard image formats. The smaller file size is worth the quality tradeoff. JPG is universally supported.
PNG is the right conversion target when the image will be used in a design workflow where transparency may be needed, where multiple save cycles are expected, where the image contains text or interface elements with sharp edges, or where the image will be used as a design asset rather than a final output. PNG is also the right choice when posting to platforms that compress uploaded images aggressively: serving a PNG source lets the platform's own compression make the size decision rather than compressing twice.
A common workflow is to convert HEIC to PNG for design work, remove the background, make edits in a design tool, and then export the finished result to JPG only at the final step when sharing.
HEIC files from modern iPhones use the Display P3 wide color gamut profile, which includes colors that standard sRGB cannot represent. This extended color range is visible in saturated reds, greens, and blues, particularly in outdoor photography.
PNG files support embedded ICC color profiles, which means a HEIC-to-PNG conversion can preserve the Display P3 profile in the output file. Whether this is useful depends on the destination: devices with wide-gamut displays will render the extended colors correctly, while sRGB-limited displays will approximate them. Converting to JPG also supports ICC profiles, though JPG handling of wide-gamut profiles has historically been less consistent.
If the conversion tool does not handle color profiles, the output may be silently converted to sRGB, which clips the colors to the sRGB gamut and produces slightly less saturated results.
Conclusion
PNG was created specifically to provide what GIF and JPG could not: a patent-free format with full lossless compression and genuine alpha channel transparency. Those properties, established in 1995 and formalized in 1996, remain the reasons designers and developers choose PNG over JPG today.
For converting iPhone HEIC photos to PNG while preserving full quality and transparency support, ToolHQ's HEIC to PNG converter processes the conversion in the browser without requiring a file upload to an external server.
Frequently Asked Questions
What is the difference between PNG and JPG compression?
JPG uses lossy compression that discards some image data to achieve smaller files. PNG uses lossless compression that preserves all data, producing larger files but no quality loss across saves.
Why would I need PNG instead of JPG from an iPhone photo?
If you need transparency support, plan to edit and re-save the image multiple times, or are using it in design work where pixel precision matters, PNG is the appropriate format.
Does converting HEIC to PNG make the file much larger?
Yes. PNG's lossless compression typically produces files several times larger than a JPG equivalent. This is the trade-off for preserved quality and transparency support.