Well if both image files have the same file path, DynaPDF will only put the image file on time into the PDF. This saves a lot of space if you have for example a logo on each page. The logo is only time in the file.
But now if you write temporary files with images from a database and you reuse the same temporary file each time? Well, only the first or the last picture is in the PDF on all pages. So to allow DynaPDF to see the difference, write all pictures to different file names. Simply ask RB for a temporay folderitem using getTemporaryFolderitem. Call CreateFolder on it and put your images inside. Later you can delete this folder when you closed the PDF. Also keep files available the whole time the PDF is not yet written. This way we can optimize and read images later when we need them. This can reduce the memory footprint.
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