A4 paper size is 210x297mm, which translates to 2480x3508 pixels at 300 DPI for print-ready quality. This is the standard paper size used in most countries outside of North America.
For high-quality printing, 300 DPI is the minimum recommended resolution. This means you need a source image of at least 2480x3508 pixels for full A4 prints. Lower resolution images can be printed but will appear less sharp.
With ImgTools, upload your image and resize to 2480x3508 for portrait A4 or 3508x2480 for landscape A4. If your source image is smaller, consider whether the upscaled quality is acceptable for your print needs.
Save as PNG for lossless quality or JPEG at 95% for high-quality prints. For professional printing, your print shop may accept PDF files, but starting with a high-resolution image is the first step.
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