Mailchimp image sizing is a block-width decision. The right export depends on builder context, visible width, padding, columns, format, source quality and whether the image needs high-density display support.
Why 600, 660 and 1320 pixels can all be true
Mailchimp's template image guidance currently says templates are generally designed for a maximum width of 600 pixels. The new builder's Image block guidance recommends images with a minimum width of 660 pixels and suggests 1320 pixels for retina/high-density preparation. Background-image guidance also references a 660-1320 pixel range for templates that are 600-660 pixels wide.
Those numbers describe different contexts. A classic template width, a new-builder content area and a 2x source for high-density displays are not one universal rule. For a two-column block, calculate the actual column width after padding. For a logo, use the display size of the logo area. For custom-coded HTML, use absolute image paths and constrain display dimensions in email-safe markup.
Size, format and retina decision table
| Decision point | Official context to respect | Practical export choice | Risk to avoid | Verification step |
|---|---|---|---|---|
| Full-width image | Template/content area and padding determine useful width. | Export to the visible content width; consider a clean 2x source when high-density clarity matters. | Uploading a huge image far larger than the content area. | Preview desktop and mobile in Mailchimp. |
| Multi-column image | Column width is a portion of the overall template/content area. | Export for the column, not the full hero width. | Tiny text or product details that collapse on mobile. | Check stacked mobile order and image balance. |
| JPG photo | JPG is a dependable email image format in Mailchimp guidance. | Use for photos and product/lifestyle images. | Repeated lossy exports around text and edges. | Compare product detail after compression. |
| PNG graphic | PNG is useful for sharp graphics and transparency. | Use for logos, icons, diagrams and UI screenshots when edges matter. | Full-width photographic PNG files becoming too heavy. | Check file weight and dark-mode contrast. |
| GIF animation | GIF can be used, but animated support and editing behavior vary. | Use only for short motion that adds meaning. | Large animation, broken editing flow or useless first frame. | Test first frame, mobile load and images-off meaning. |
| RGB color | Mailchimp recommends RGB rather than CMYK for campaign images. | Export web/email copies in RGB. | Print-mode color shifts or poor screen display. | Preview important brand/product colors. |
| DPI metadata | Mailchimp notes 72 dpi is generally sufficient for web but not required. | Use pixel dimensions and displayed width as the real sharpness check. | Trusting a DPI label while the image is too small. | Inspect actual pixel width before upload. |
JPG, PNG and GIF are not interchangeable
Use JPG for photographs
JPG is usually the practical delivery format for product photos, portraits, lifestyle images and textured scenes. It balances detail and file weight well, but it is lossy. Avoid repeated saves and be careful with small text, gradients and sharp product edges.
Use PNG for edges and transparency
PNG is helpful for transparent logos, icons, diagrams, charts and screenshots. It can preserve crisp edges, but it may create large files for photographs. A transparent logo PNG may be correct; a full campaign hero exported as PNG may be unnecessarily heavy.
Use GIF sparingly
Mailchimp's HTML email limitations caution that animated GIF support is not uniform across email clients, and editing animated content in a photo editor can break the animation. Use GIFs only when motion adds value, keep the first frame meaningful, and do not rely on motion to communicate the only call to action.
RGB versus CMYK
Images for Mailchimp email campaigns should be RGB. CMYK is built for print workflows, and Mailchimp's guidance warns that some browsers and email programs cannot display CMYK images well. If the image came from a print catalog, packaging file or designer handoff, export a fresh RGB campaign copy before upload.
Crop, scale, padding and stretch
These are different actions. Crop removes edges to fit a proportion. Scale changes size while preserving proportions. Padding reduces the visible content area. Stretch distorts the image and should not be used to force a product, person or logo into a block. If an asset does not fit a block, make a new crop or choose a block that matches the image.
Background images need extra caution
Mailchimp's background-image guidance says the new builder supports background images for the entire email, while the legacy builder supports them in specific sections and custom templates. It also warns that multi-column background-image sections may distort on mobile. Always set a fallback color and check text contrast without relying on the image.
Where to go next
FAQ
Should a Mailchimp image always be 1320 pixels wide?
No. The 1320-pixel idea applies to high-density preparation in the new builder context. A two-column thumbnail, logo or small icon should be sized for its actual displayed role.
Is 600 pixels or 660 pixels the correct Mailchimp email width?
It depends on context. Mailchimp describes templates generally around 600 pixels, while the new builder Image block guidance recommends a 660-pixel minimum. Always confirm the builder and content block.
Is JPG or PNG better for Mailchimp product images?
JPG is usually better for product photographs. PNG is better for transparency, graphics, screenshots or logos with sharp edges. The right choice depends on the asset, not the platform alone.
Can Mailchimp use CMYK images?
Mailchimp recommends RGB for campaign images because CMYK is print-oriented and may display poorly in browsers or email programs. Re-export a web/email copy in RGB.
Does DPI control Mailchimp image sharpness?
No. Pixel dimensions and displayed width are the practical screen-sharpness factors. A 72 dpi label does not make a too-small image sharp when enlarged.
