Hi,
– Compression:
It’s not image but PDF objects compression. It will work only with some elements and if this objects possible to compress, however in most cases it will not affect PDF size too much.
– Flatten:
No – PDF fields will remain editable and it will be possible to copy text from PDF.
Yes – PDF fields will be read-only and it will be possible to copy text from PDF.
Full – PDF fields and all other content will be converted to “image”, so none of content can be copied from PDF. It’s not recommended to use this option with PDFs which has a lot of pages as it’s resource and time hungry operation.
We remain at your service.