Image File Size Guide: KB and MB Targets for Every Use Case
Last reviewed: April 2026
Different platforms enforce wildly different file size limits, and the wrong number can mean a rejected upload, a frustrating support ticket, or a passport application sent back to the start. This guide collects the file size targets that actually matter — for passports, social media, e-commerce, email, and the web — with the use cases behind each one.
If you already know your target, drop your photo into Sukat, type in the KB or MB, and it'll find the highest quality version that fits.
Quick Reference
Skip ahead to the size you need:
- Under 20 KB — small signatures, ID thumbnails
- 20–50 KB — small portal uploads, scanned signatures
- 50–100 KB — passport photos, profile pictures
- 100–200 KB — blog thumbnails, social previews
- 200–500 KB — featured images, product photos
- 500 KB – 1 MB — portfolio shots, large blog images
- 1–2 MB — email-friendly attachments
- 2–5 MB — hero images, high-resolution prints
When You Need Each Size
Under 20 KB
Tiny signatures on legacy document systems, low-resolution IDs for older databases, thumbnails for search index previews.
The 20 KB ceiling is unforgiving. At this size, expect visible compression artifacts on photos and downscaling to roughly 400–600 pixels on the long edge. Use it only when a portal explicitly demands it — usually older systems with hardcoded legacy limits.
20 to 50 KB
ID badges, employee photo databases, small portal uploads, scanned signatures.
This range is common on legacy upload portals that haven't been updated since storage was expensive. Sukat will downscale dimensions automatically if your image can't fit at quality 1, so you always end up under the limit.
50 to 100 KB
LinkedIn profile photos, X/Twitter avatars, ID portal uploads in many countries, college admission portals, job application sites.
100 KB is the single most-searched compression target. It's the universal "small but not tiny" file size — small enough for most upload limits, large enough for a recognisable face. Most professional headshots compress comfortably to this range without visible quality loss.
100 to 200 KB
Blog thumbnail images, WordPress featured images, social media post images, email signature graphics.
This is the sweet spot for web performance work. Images at 100–200 KB load fast on mobile, fit easily under most CMS limits, and still look sharp on retina displays at standard thumbnail sizes (around 600–800 pixels wide).
200 to 500 KB
Shopify product photos, Amazon listing images, blog featured images at full width, Substack and Medium hero images.
E-commerce platforms typically allow images up to 1–2 MB but recommend 200–500 KB for optimal page speed. At 500 KB, you can serve a 1500-pixel-wide image with very little compression — perfect for product detail shots that need to handle zoom.
500 KB to 1 MB
Portfolio site work, full-width blog hero images, magazine-style layouts, gallery thumbnails.
Once you cross 500 KB you're trading load speed for image quality. This range is appropriate for visual portfolios, photography blogs, and any site where image quality is the product. Below 1 MB still loads fast on broadband and most mobile connections.
1 to 2 MB
Email attachments, presentation slides, social media uploads at maximum quality, document submissions.
Most email providers allow attachments up to 25 MB total, but individual recipients often have stricter inbox quotas. Keeping each image under 2 MB means a typical 5–10 image gallery fits comfortably within most email limits.
2 to 5 MB
Print-ready images, high-resolution hero images, Instagram and Facebook uploads at native quality, archival storage.
This is the ceiling for typical web use. Images above 5 MB should generally be reserved for print or download — at 2–5 MB you can serve a full 4K-width hero image with minimal visible compression.
Use Case Reference
Passport and Visa Photos
Passport and visa photo requirements vary by country. Dimensions are usually fixed in millimetres or inches, and the file size limit is often expressed in KB.
- Philippines passport (DFA) — 35×45 mm (3.5×4.5 cm), plain white background, JPEG. File size typically under 300 KB. The current DFA ePassport standard is white background — the older blue background rule no longer applies. The same 35×45 mm format is also used for NBI clearances, school IDs, OFW documents, and most other Philippine government IDs.
- United States passport — 2×2 inches (51×51 mm) at 300 DPI, JPG format, file size typically under 240 KB for online submissions.
- Schengen visa (EU) — 35×45 mm, file size usually requested under 500 KB across most embassy portals.
- UK passport (HM Passport Office) — Digital photos must be at least 600×750 pixels and between 50 KB and 10 MB.
- Canada (IRCC) — 35×45 mm, file size between 60 KB and 240 KB for most online forms.
- Australia (DFAT) — 35×45 mm, file size between 100 KB and 1 MB.
- Japan visa — 35×45 mm, file size typically under 240 KB for online consular submissions.
For any of these, drop your photo into Sukat, set the country's target, and let it land under the limit.
Always verify the current requirements on the official portal before submitting — some embassies update their requirements between visa cycles.
Social Media
- LinkedIn profile photo — 400×400 pixels recommended, max 8 MB, but compress to 200 KB for fastest load.
- X (Twitter) profile photo — 400×400 pixels, max 2 MB. Compress to 100–200 KB for clean load.
- Twitter header — 1500×500 pixels, max 5 MB.
- WhatsApp profile photo — Auto-compressed by the app, but uploading a pre-compressed 100 KB image avoids the platform's lossy re-compression.
- Instagram post — 1080×1080 (square), 1080×1350 (portrait), or 1080×566 (landscape), max 8 MB.
- Discord avatar — 128×128 minimum, 8 MB maximum, but anything over 1 MB starts to lag in chat previews.
- Facebook profile photo — 170×170 displayed, 320×320 recommended, max 4 MB.
E-commerce
- Shopify — Up to 4472×4472 pixels, 20 MB max, but the platform recommends keeping product images under 70 KB for fastest page load.
- Amazon Seller Central — Minimum 1000×1000 pixels for zoom, max 10 MB. Recommend 500 KB–1 MB for upload.
- eBay — Up to 7 MB per image, but most listings perform better at 500 KB–1 MB.
- Etsy — Up to 10 MB, but compresses to roughly 1500 pixels on display anyway.
Blogs and CMS
- WordPress — Default upload limit is set by your hosting provider, usually 8–64 MB. For performance, compress to 200–500 KB.
- Medium — Up to 25 MB per image, but the platform re-compresses uploads. Pre-compressing to 500 KB prevents double-compression artifacts.
- Substack — 4 MB per image, but compress to 200–500 KB for newsletter delivery weight.
- Ghost — Depends on hosting; typical recommended ceiling is 1 MB for featured images.
Email Attachments
- Gmail — 25 MB per email total. For a multi-image email, keep each image under 2 MB.
- Outlook — 20 MB total in Outlook.com, 33 MB in Microsoft 365 (configurable). Keep each image under 1 MB for safety.
- Yahoo Mail — 25 MB total.
- iCloud Mail — 20 MB total, with Mail Drop kicking in for larger attachments.
For sharing many photos at once, ZIP them and target the ZIP under 25 MB total — Sukat outputs a single ZIP for batch jobs in one click.
Format Notes
The file format you choose has a bigger impact on size than most people realise.
- WebP — typically 25–35% smaller than JPEG at the same visible quality. Universally supported in browsers since 2020. Sukat's default output. Best choice for any web use case.
- JPEG — universally supported including older email clients and printing services. Best choice when the destination explicitly requests JPG.
- PNG — only worth using when you need transparency or pixel-perfect output (logos, screenshots, illustrations with text). For photos, PNG produces files 3–5× larger than JPEG with no visible quality difference.
- HEIC/HEIF — what your iPhone records by default. Smaller files than JPEG but unsupported by Windows and most non-Apple platforms. Convert to JPG or WebP before sharing or uploading.
- AVIF — newer than WebP, slightly smaller files at the same quality, but support is still spotty in older browsers. Use when you control the destination.
How to Compress to an Exact Size
Drop your image into Sukat, enter your target in KB or MB, and it'll find the highest quality version that fits under your ceiling. If even quality 1 produces a file larger than your target, it scales dimensions down as a last resort — so you always end up under the limit.
The whole thing runs locally in your browser. No uploads, no signups, no watermarks. Works for JPG, PNG, WebP, GIF, AVIF, and HEIC inputs. For the full mechanics, see How It Works.
FAQ
Why does the same KB target produce different image quality on different photos?
File size after compression depends on the content of the image, not just the dimensions. A photo with lots of detail (foliage, crowds, textures) compresses less efficiently than a photo with smooth gradients (sky, plain backgrounds). Sukat finds the highest quality that fits your target for that specific image.
What's the smallest practical file size for a recognisable face?
Around 15–20 KB for a 600×600 pixel headshot. Below that, JPEG compression artifacts become visible enough to obscure facial features.
Can I increase image file size if it's too small?
Sukat compresses; it doesn't pad files to artificially hit a minimum. If a portal requires a minimum size, raise the dimensions or use a less efficient format (PNG instead of WebP) to inflate the file.
Why does my upload still get rejected even when the file size is right?
Portals often check more than file size — dimensions, aspect ratio, format, colour space, and minimum file size all factor in. Check every requirement on the original form, not just the KB ceiling.
Does compressing damage my original file?
No. Sukat downloads a new compressed copy and never modifies the file on your device.