Image specs for A5 & A6 postcards (and social sharing)

Web image specifications

Web images are used on the action web pages: landing, selection, completion. They are also be used when sharing on social media. They need to be web optimised quality (few hundred KB) so the page load time is fast. Technically this means:

1. Size: 500 pixels wide x 352 pixels high (or a ratio of 1.4187)
2. Colour model: RGB colours
3. Resolution: 72 dpi and in any web friendly format (png/png/tiff/webp).

Print image specifications for A5/A6

The print version of the image(s) will appear on the printed postcard, so it can be slightly different from the web version. They needs to be high quality (2-8 MB) so the print quality is good. Technically this means:

1. Size: 2480 pixels wide x 1748 pixels high (= 210mm wide x 148mm) or flip that for tall postcards
2. Crop area: 5mm (60 pixels at 300 dpi) on each side so the image continues, but no critical content is in this margin. This will be cut off in the printing process.
3. Margin: A further 5mm (60 pixels at 300 dpi) margin 'unsafe' area (on top of the crop area) with no crucial design elements as the cutting may drift into this space.
4. No white border/crop marks unless you want this printed.
5. Resolution: 300 dpi - note a lower DPI value will mean a lower print quality and different pixel-to-mm conversion than above
6. Colour model: CMYK for print
7. File format: JPEG only (not PDF nor png/tiff/webp as these don't support CMYK colours).

Social sharing specifications

To automatically include a properly sized image when sharing to Facebook, Twitter/X, WhatsApp, Slack and much more, provide an image with the following specifications (open-graph image spec):

1. 1200 x 630 pixels max
2. Under 300kb in size (max 500kb but test it)
3. It can be any web supported format: jpeg, png, webp, svg, etc.