Image Size Guide: The Right Dimensions for Web, Social Media & Email

Every platform has its own recommended image dimensions, and using the wrong size means your images get cropped awkwardly, look blurry, or load slower than they should. Here's a practical reference for the most common sizes you'll need, plus tips for resizing efficiently.

Website Images

• Hero/banner images — 1920×1080 pixels is the standard for full-width hero sections. It covers most desktop screens without being excessively large.
• Blog post images — 1200×630 works well for most blog layouts and doubles as a good Open Graph image size.
• Thumbnails — 300×300 or 400×300 for card-style layouts. Keep these under 50KB for fast loading.
• Favicons — 32×32 for the browser tab, 180×180 for Apple touch icons, 512×512 for PWA icons.

Social Media

Social platforms are notoriously specific about image dimensions. Using the wrong size means your image gets cropped or padded with ugly borders.

• Open Graph (link previews) — 1200×630. This is what shows when you share a link on Facebook, LinkedIn, Twitter/X, and most messaging apps.
• Instagram post — 1080×1080 (square), 1080×1350 (portrait), or 1080×566 (landscape).
• Twitter/X post — 1200×675 for in-stream images. 1500×500 for the header banner.
• LinkedIn post — 1200×627 for link shares, 1080×1080 for image posts.
• YouTube thumbnail — 1280×720 with a minimum width of 640 pixels.

Email

• Email header image — 600×200 pixels. Most email clients render at 600px wide, so this is the safe maximum.
• Email signature logo — 300×100 or smaller. Keep the file size under 30KB so it doesn't slow down email loading.
• Inline images — 600px wide maximum. Anything wider gets scaled down by the email client, which can look blurry.

Print

Print dimensions depend on the physical size and DPI (dots per inch). For standard 300 DPI printing:

• 4×6 photo — 1200×1800 pixels
• 8.5×11 letter — 2550×3300 pixels
• A4 — 2480×3508 pixels
• Business card — 1050×600 pixels

Contain vs Fill: Which Resize Mode to Use

When resizing an image to specific dimensions, you have two main options:

Contain fits the entire image within the target dimensions while preserving the aspect ratio. If the proportions don't match, you get padding (usually white) on the sides or top/bottom. This is the safe choice when you don't want anything cropped.

Fill stretches the image to exactly match the target dimensions. If the aspect ratio differs, the image gets distorted. Use this only when your source image already has roughly the right proportions, or when exact pixel dimensions matter more than visual accuracy.

How to Resize Quickly

You can resize images to any of these dimensions using Convertly's image resizer. Drop your images, enter the target width and height, choose contain or fill mode, and download the results. It handles JPG, PNG, and WebP, processes multiple files at once, and runs entirely in your browser — no upload required.

File Size Tips

Dimensions are only half the equation — file size matters too. A few rules of thumb:

• For web images, aim for under 200KB per image. Hero images can be up to 500KB.
• Use JPG for photos, PNG for graphics with sharp edges, WebP for the best compression.
• If an image is too large after resizing, try converting it to WebP — you'll typically save 25-35% compared to JPG.
• Thumbnails should be under 50KB. If they're larger, reduce the dimensions or increase compression.