HEIC vs JPG vs PNG — Image Format Comparison Guide

Digital images come in dozens of formats, but three dominate modern workflows: HEIC (Apple's default since iOS 11), JPG/JPEG (the universal photograph standard), and PNG (the lossless format with transparency support).

According to Apple, iPhones have captured over 3 trillion photographs in HEIC format since it became the default in iOS 11 (2017). Yet according to W3Techs, JPG remains the most common image format on the web, used by 74.5% of all websites as of 2024, followed by PNG at 72.4% and WebP at 35.2%.

HEIC (High Efficiency Image Container) — technically a subset of the broader HEIF standard (ISO 23008-12) — uses HEVC (H.265) video codec technology to compress still images. This gives it a remarkable efficiency advantage over JPG.

Key advantages: • ~50% smaller files at equivalent visual quality compared to JPG. According to Apple's engineering team, a typical 12-megapixel iPhone photo occupies approximately 1.8 MB in HEIC versus 3.5 MB in JPG — with no perceptible quality difference. • 16-bit color depth — Supports wider color gamuts (Display P3, Rec. 2020) for more accurate color reproduction than JPG's 8-bit limitation. • Alpha transparency — Unlike JPG, HEIC supports transparent backgrounds. • Image sequences — A single HEIC file can store burst photos, live photos, and depth maps — capabilities JPG cannot match. • Non-destructive edits — HEIC can store editing instructions (rotations, crops) as metadata without recompressing the image.

Key limitations: • Compatibility — Windows requires the HEIF Image Extensions codec (free from Microsoft Store). Older Android versions, many web applications, and legacy software cannot open HEIC files natively. This is the single largest barrier to adoption outside the Apple ecosystem. • Editing support — Adobe Photoshop added HEIC support in 2020, but many image editors and web platforms still cannot import HEIC directly. • Patent licensing — HEVC compression is covered by multiple patent pools (MPEG LA, Access Advance), creating licensing complexity for software developers. This partially explains slower adoption compared to royalty-free alternatives like WebP and AVIF.

When to convert HEIC to PDF: Use AuraPDF's HEIC to PDF converter when you need to share iPhone photos as universally compatible documents — portfolios, reports, or archival records.

JPG (JPEG) has been the dominant photograph format for over 30 years. Standardized as ISO/IEC 10918 in 1994, JPEG compression uses the Discrete Cosine Transform (DCT) to achieve significant size reduction at the cost of some quality loss.

Key advantages: • Universal compatibility — Every device, browser, application, and operating system supports JPG. According to the JPEG Committee, the format is supported by over 10 billion active devices worldwide. • Adjustable quality — JPG offers a quality slider (1–100) that provides fine-grained control over the size-quality tradeoff. Quality 85–95 is visually indistinguishable from the original for most photographs while achieving 5–10× compression. • Mature ecosystem — Three decades of tooling means JPG is supported by every photo editor, web platform, CMS, printer, and document tool in existence. • Efficient for photographs — DCT compression exploits the statistical properties of natural photographs (smooth gradients, fine texture) to achieve excellent compression ratios on photographic content.

Key limitations: • Lossy only — Every save operation recompresses the image, causing cumulative quality degradation (generation loss). Editing a JPG 10 times at quality 90 produces visibly worse results than saving once at quality 90. • No transparency — JPG does not support alpha channels. Transparent areas are flattened to a solid color (usually white or black). • 8-bit color — Limited to 16.7 million colors per channel. Insufficient for HDR content or wide-gamut workflows. • Compression artifacts — At low quality settings, JPG produces visible "ringing" around sharp edges and "blockiness" in smooth gradients — characteristic artifacts of DCT quantization.

When to convert JPG to PDF: Use AuraPDF's JPG to PDF converter to compile photo collections into organized documents, create scanned-document PDFs, or prepare images for print submission.

PNG (Portable Network Graphics) was created in 1996 by the W3C as a patent-free replacement for GIF. Its lossless DEFLATE compression preserves every pixel exactly as captured — making it the format of choice for graphics, screenshots, and images where precision matters.

Key advantages: • Lossless compression — No quality loss, no matter how many times the file is saved. The decompressed image is bit-for-bit identical to the original. • Full transparency — PNG supports 8-bit alpha channels, enabling smooth gradients from fully opaque to fully transparent. This is essential for logos, UI elements, and graphics composited over backgrounds. • Wide color support — PNG supports up to 48-bit RGB color (16 bits per channel), making it suitable for professional workflows and scientific imaging. • Sharp edges — PNG excels at encoding images with hard edges, text, line art, and solid color areas — content that JPG handles poorly due to DCT artifacts.

Key limitations: • Large file sizes — Lossless compression means PNG files are significantly larger than JPG for photographic content. A 12-megapixel photograph may occupy 15–25 MB as PNG versus 3–6 MB as JPG — a 3–5× size premium for typically imperceptible quality gains on photographs. • No native CMYK — PNG supports RGB and grayscale but not CMYK color spaces, limiting its use in commercial print workflows. • Slow compression — Maximum PNG compression (level 9) is computationally expensive compared to JPG encoding.

According to Google's WebP research, PNG is "optimal for images with fewer than 256 colors or images requiring transparency" while JPG is optimal for "continuous-tone photographs with complex color distributions." This aligns with the practical guideline: use PNG for graphics and screenshots, JPG for photographs.

When to convert PNG to PDF: Use AuraPDF's PNG to PDF converter for design portfolios, technical documentation with screenshots, diagrams, and any content requiring pixel-perfect reproduction.

When converting images to PDF documents, the source format affects both the resulting PDF's quality and file size:

Compression considerations: When images are embedded into a PDF, they can be recompressed using the PDF's internal compression (see our PDF Compression guide). This means the source format's compression is less important than the image's pixel quality — a high-quality JPG and a PNG of the same image will produce nearly identical PDFs after PDF-level compression.

Resolution guidance: For screen-only PDFs, source images at 150 DPI are sufficient. For printable PDFs, aim for 300 DPI at the intended print size. See our DPI and Resolution guide for detailed recommendations.

Best practice: When quality is paramount, always provide the highest-quality source available. Start with PNG or high-quality JPG (95+), then let AuraPDF's compression tools optimize the final PDF. Starting from a heavily compressed source limits the quality ceiling of the resulting PDF.