What is a linked image and what is an inline image?
Linked Image
If you use a linked image in your message, then the message itself will only contain a reference to this image which itself is stored on a web server. The actual image data will not be part of the message and will therefore also not be included in the message data that is sent from LISTSERV Maestro, via the mail servers, to the recipient's email client.
When the recipient's email client displays the message, it will then load the image from its location on the web server "just-in-time", at the moment the message is being displayed.
Advantages: The message itself remains relatively small, since it does not contain the image data, but only a textual reference. In comparison, the image data is always much larger than such a reference. So a message with linked images is delivered more quickly and takes up less bandwidth.
Disadvantages: Many modern email clients do initially not display linked
images when the message is first opened by the recipient. They leave it up to the recipient to decide if he
wants to see linked images or not. So the actual images are only loaded and displayed when, and if, the
user says so. Or linked images can also fail to load if the recipient is viewing the email while he
is offline (for example on a laptop that is currently not connected to the Internet).
In both cases, your message may appear broken or ugly while the images are not displayed.
And if the images contain an important part of your message, the message may even appear nonsensical
without them.
Inline Image
If you use an inline image in your message, then the message will contain the actual image data (similar to an attachment). This means that the image data will be part of the message data which is sent from LISTSERV Maestro, via the mail servers, to the recipient's email client.
When the recipient's email client displays the message, it already has all the image data right there in the message and uses it to display the image.
Advantages: Email clients usually do not block inline images but display them right away (although some clients may still block them until the user opts to display them). In addition, inline images are displayed without problems even if the recipient is viewing the email while he is offline (for example on a laptop that is currently not connected to the Internet). Therefore, with inline images you have a good chance that your message will appear exactly as intended, with all images in place.
Disadvantages: Including the image data in the message makes the message larger.
And a copy of the data of each inline image will be included in each individual message, for each individual
recipient. Especially if you have very many recipients, this "multiplication" of the image data can take
up a considerable amount of your delivery bandwidth, slowing down delivery.
Another disadvantage is that many email clients display inline images not only in the message itself, but
also in the list of attachments. Depending on what images you have, this effect may be undesired.
Unsure which option is best?
See here for help with choosing the right option.