Diagram translator: translate the labels in a diagram image

A translated diagram has to say the same thing as the original, in the same place, with the same numbers. That is easy when the diagram still lives in its source file and hard when all you have is a flattened image in an old manual. This page explains which situation you are in and how to translate a diagram image without redrawing it.

Source file or image? Choose the right method

How to translate a diagram image

1. Export the figure on its own. Crop to the diagram plus its legend. Keep the file under 10 MB in JPG, PNG or WebP, at a size where you can read every label yourself.
2. Open the image translator, choose the source language or auto-detect, and choose the target language.
3. Select the Technical Documentation mode in the mode menu, which shows "Default mode" unless you saved another default. The menu is shown on wide screens; on a smaller one, signed-in users can save a default business type in their profile. The mode instructs the model to keep a clear visual hierarchy (headings, subheadings, body text, annotations), use precise technical terminology and translate technical specifications and measurements correctly. It is an instruction, not a guarantee, which is why the review step below matters.
4. Add your terminology if you are on the Pro plan or above. The custom AI instructions field (up to 1,000 characters) accepts notes such as "Translate 'bracket' as 'soporte'" or "Do not translate part names in capitals".
5. Review against the original with the checklist below, then download the translated figure and replace it in your document.

For a manual with dozens of figures, batch translation processes up to 10 images per run, each in one or more target languages (50 translated images at most). Teams that generate figures automatically can call the image translation API. Both are available from the Pro plan. If the source manual is in German, the German image translator page lists the terms, signal words and number formats to watch.

What to check in a translated diagram

Numbers and identifiers

• Part numbers, reference designators (R12, C4), dimensions, tolerances and units must match the original exactly.
• Callout numbers (1, 2, 3 pointing to parts) must stay in the same positions so the legend still matches.

Labels and space

Labels are short, and short strings expand the most when translated: IBM guidance quoted by the W3C puts the average expansion of English strings of up to 10 characters at 200–300% when they are translated into European languages (W3C). German compound nouns make single words long and hard to fit. Look for labels that were shortened, abbreviated or moved to make them fit, and check that leader lines still point to the right part.

Terminology

A diagram must use the same term as the manual text around it. If the manual says "torque wrench", the figure cannot say "tightening key". Keep a short glossary and, on the Pro plan or above, paste the key terms into the custom AI instructions.

Symbols and safety text

Graphical symbols (safety pictograms, electrical symbols) are not meant to be translated: compare them with the original to make sure they came out unchanged. Warning and caution text needs a human check: wording in safety labels can be regulated (the GB CLP Regulation, for example, sets the signal words "Danger" and "Warning" for chemical labels, HSE), and a generated translation is not a substitute for a reviewed one.

What stays outside the image

Captions, figure titles in the document body and alt text are not part of the image. Translate them with the rest of the text so the figure and its caption say the same thing.

Diagrams vs charts

Charts and infographics raise different problems: number formats, decimal separators and legends. They have their own guide: chart and infographic translator. Screenshots of software interfaces are covered in the screenshot translator guide.