By sending images as inline (also called embedded) images appear in the email even if the recipient has disabled automatic images downloading/display.
The pictures below demonstrate this. They are from a desktop, mobile app and another web-based email client.
With nuevoMailer in order to send your images as embedded you must have these images stored in the assets folder of your nuevoMailer installation (or a subdirectory within). When you use the image upload utility your images are uploaded by default into the assets folder.
You can embed your images with Html or Multipart newsletters. Not plain text ones.
However, email clients are becoming "smarter" and improving their filters so that images are blocked even if they are sent as embedded.
When images are sent embedded in some email clients appear as attachments.
There is one small disadvantage when sending images embedded. The subscriber since he can see the images he may not be inclined to explicitly allow image downloading and therefore the "open" is not captured. On the other hand it makes it easier, more enticing to click on an image.