||In Poco 3, there are a couple of new features related to HTML
display. Take a look at the small toolbar above the preview pane.
Among the other icons, there are three of note:
If you don't see these buttons, you may have turned them off. To
turn them on, right-click in the small toolbar and select Show
Before explaining how the buttons differ, here's what they all have in common:
If any of the three security features is active (the button will show a dark
background when using the default colors), no images will be fetched from external
sources on the Internet.
Here's what each button does, in order from left to right:
button : "Toggle image downloading," same as Poco 2's
"Download external images" button.
- This stops Poco from retrieving external images when you open
an HTML message. This option is useful for preventing spam from
verifying your address via webbugs, for example.
Note: If an image is already in the cache from a previous fetch, it will
still appear if only Toggle Image Downloading is disabled.
- Tri-color button with black censorship boxes : Sanitize
- "Sanitize Message" does much more than merely avoid the
webbugs, background sounds and image HTML tags, etc., and mangles
the possibly-malicious script and external references.
Instead of saying something like:
<img height=1 width=1 src=http://WeAreSpyingOnYou.com?PersonalData=YourEmailAddress>
A Poco3-sanitized webbug will say something like the following
<sanitized_img height=1 width=1 sanitized_src=http://WeAreSpyingOnYou.com?PersonalData=YourEmailAddress>
This mangling means the HTML command is not executed, so the
external data is not requested. The effect is display-only; the
email is itself not changed.
The idea is to increase security and privacy. Spammers use
webbugs and regular external images as a form of return-receipt:
when you read the email, the image is fetched and your email
address is validated. This can leave you open to a lot more spam.
Since it's a toggle, you can easily enable it for a particular
email if you trust the source.
Meanwhile, "Download External Images" (new form: "Toggle Image
Downloading") simply enables or disables the fetching of external
images only. The content of the email is not changed even for
display. A placeholder the size of the original picture appears in
the email with a black exclamation mark on a yellow background,
indicating that downloading is disabled. This placeholder won't
appear if "Sanitize Message" is enabled.
With image downloading disabled, a newsletter will have a lot
of frames with black-on-yellow exclamation-mark placeholders, but
the form of the newsletter will be preserved. A sanitized
newsletter will look quite different.
- Gray envelope icon : Strip HTML.
- This will basically turn an HTML message into a plaintext