Feature01
A preview is a decision aid
A thumbnail, media view, or document rendering can help a recipient confirm they opened the right delivery. It reduces needless downloads without silently replacing the original file.
Feature02
Not every format previews
Preview availability depends on the format and safe browser support. Archives, specialist project formats, and some media codecs may still need a download and the appropriate local software.
Feature03
Sensitive content needs the same judgment
If the material should not render in a browser, disable previews and use suitable transfer controls. A preview setting does not change who is authorized to see the content.
Edge cases
Before the handoff
Does preview compress my original?
The preview is a viewing aid; the uploaded original remains the delivery file.
Why is a preview missing?
The file may use an unsupported format or codec, or the sender may have disabled previews.