Image Formats Explained: JPEG, PNG, WebP, AVIF, HEIC, and Resizing Order

JPEG is a lossy format designed for photographic content. It usually produces small files for photos with gradients and many colors. It does not support transparency and can create artifacts around sharp edges, text, and screenshots. Re-saving a JPEG repeatedly can degrade quality. Use it for ordinary photos when compatibility matters, but avoid it for logos, UI screenshots, line art, and images that need alpha transparency.

PNG is lossless and supports transparency, making it useful for logos, diagrams, screenshots, and graphics with hard edges. The tradeoff is file size, especially for large photos. A PNG product screenshot may be perfect, while a PNG camera photo may be unnecessarily huge. If the image has text or needs transparent background, PNG is often safer than JPEG. If it is a large photo, consider modern lossy formats instead.

WebP and AVIF can produce smaller web images than older formats in many cases. They support modern compression features, and WebP also supports transparency. AVIF can be excellent for compression but may be slower to encode and less predictable in older workflows. Format choice should follow the destination. A website can often serve modern formats with fallbacks, while a government upload form or older CMS may still require JPEG or PNG.

Many phones can capture HEIC or HEIF images because they offer efficient storage. The problem is compatibility. Some browsers, upload forms, and desktop workflows still expect JPEG or PNG. Converting HEIC to JPEG can make sharing easier, but it may remove metadata or change color handling depending on the tool. Keep originals when image quality or provenance matters, and export compatible copies for the destination.

If an image is 4000 pixels wide but will display at 1200 pixels, resizing first usually saves more than aggressive compression. Compression should be tuned on the final dimensions. Otherwise you may waste effort compressing pixels that will be thrown away later. The same rule applies to batches: establish target dimensions, test one image, then apply settings to the rest.

Image conversion can strip or preserve metadata depending on settings. It can also change how orientation tags are handled. A phone photo may look correct before conversion and rotate unexpectedly afterward if the metadata was removed without rotating pixels. Inspect the exported file, not only the source preview. If privacy matters, review EXIF after the final export.

Choose one representative image from the batch. Crop and resize it to the target dimensions. Export to the intended format. Compare quality, file size, transparency, orientation, and metadata. Only then process the full batch. After batch export, sample a few edge cases: the smallest image, largest image, transparent image, text-heavy image, and phone photo. Batch work is fast only when the settings were proven on realistic examples first.