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{imprint}_{bookID}_{free-text}_fig[{nn][}{a]{.[{ext]}

with:

• imprint and bookID as above.
• free-text is optional and can be used for anthologies to specify the name of the author
• nn is a two-digit numbering 01 - 99
• a is optional and can be used to indicate figures that belong together, for example .._fig02a.jpg and .._fig02b.jpg
• ext is the file extension of the image, either "jpg" or "pdf"

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