Separate the picture from the document
Use your PDF viewer's permitted save or export options where available. If you take a screenshot, zoom enough to obtain a readable picture and crop away toolbars and unrelated text. Do not upload a confidential document merely to search one public illustration.
Follow both visual and written clues
- Note the page number, caption and visible credit.
- Search the image copy through a suitable image-search tool.
- Search a distinctive caption phrase separately.
- Compare candidate publications with the PDF's references.
A chart reproduced in a report may originate in a cited paper rather than on the report publisher's website. The chart's appearance alone may not reveal whether numbers were updated. Check labels and dates against the source document.
Make a useful source note
Record the PDF URL, page number and any candidate original together. A match to the same illustration does not verify the report's surrounding claims. If the PDF gives no credit and the search finds only reposts, describe the illustration as unattributed rather than assigning authorship to the earliest result you happened to see.
Continue with photo formats and metadata.