What does the size of an email mean?
When we say that an email becomes larger, we do not mean its visible appearance on the screen. We mean the technical amount of data in the message: the number of bytes transferred during delivery and stored by the recipient. An email contains more than the text you see in the editor. It can include the subject, sender and recipient information, formatting data, HTML code, technical transfer information, images, and other files.
A short text without images is therefore usually very small. As soon as you add images, the data volume increases. This becomes especially noticeable when you embed images in the mailing. The complete image files then become part of the email and are transferred together with the message to the recipients.
What makes an email larger?
The main factors are images, attachments, and extensive HTML content. The decisive factor is the actual file size, not the visible dimensions of an image. A small image can require several megabytes because of high resolution or an unsuitable file format. Conversely, a larger image may need much less storage when it has been compressed appropriately.
Embedded images also require technical encoding for email delivery. The image data is converted into a format that can be transferred reliably through different mail servers. This can increase the image data by roughly one third. A 1 MB image file may therefore occupy about 1.3 MB inside the email. Several images add up accordingly.
What does this mean for mailing volume?
Mailing volume is the total amount of data generated by your mailings. A single message containing three images of 1 MB each may become approximately 4 MB after encoding. If the same message is sent to many recipients, the total volume can become substantial. With 1,000 recipients, this could amount to several gigabytes of transferred message data, depending on how the system counts the volume.
In myconvento, an additional charge may apply once monthly mailing volume exceeds. The exact billing depends on how mailing volume is defined and calculated in your contract and account. The basic rule is simple: the larger the individual message and the larger the recipient group, the faster the total volume grows. You should therefore assess embedded images not only by their appearance, but also by their file size and the number of recipients.
What does a large email mean for the recipient?
The recipient must download and process the complete message. This can result in longer loading times on slow connections or mobile devices. It also uses more mobile data and requires more mailbox storage. Mail servers and mail programs may impose size limits. If a message is too large, it may be delayed, rejected, or processed only partially.
The display can also vary. Outlook, webmail, and mobile mail programs handle HTML and images differently. A large mailing may respond more slowly or require more resources when opened. Embedding images is therefore not a guarantee that every image will always be displayed. Security and privacy settings may still restrict image display.
What does a large email mean for the sender?
For you as the sender, a large mailing first means higher mailing volume. This can lead to contractual limits or additional charges. Large messages also require more time to process and transfer. For very large mailings, the load on the sending infrastructure may increase, and individual recipient servers may reject the message because of its size.
A large message also makes quality assurance more important. Check whether images appear correctly in different mail programs, whether loading times are acceptable, and whether the message works well on mobile devices. For important mailings, send a test with the actual content and, if possible, a realistic recipient group.
How can you limit mailing volume?
Check the file size of your images before inserting them. Use suitable formats, avoid unnecessarily high resolutions, and compress photos and graphics for email use. Remove images that are not needed to understand the message. A logo and one central illustration may be useful; many large photos can increase the volume quickly.
In myconvento, the embedding setting applies to all images in the entire dispatch job. You cannot embed individual images while leaving others as external references. Consider the mailing as a whole and decide based on its content, number of images, file sizes, and recipient group. If immediate display is particularly important, embedding may be useful. If the mailing contains many large images or the volume should remain as small as possible, leaving images external may be preferable.
Summary
An email becomes larger when more technical data has to be transferred. Embedded images increase the message size because the complete image files are sent together with the text. Encoding can increase the image data further. For the recipient, loading time, data use, and mailbox storage may increase. For the sender, mailing volume, processing effort, and potentially costs increase. Check image sizes and recipient numbers before sending, and run a test mailing for important communications.
