Email attachments are one of the certain ways to attract your recipient’s attention.

What are email attachments? They are files that are added to the email message bringing extra value to it. These may be files of different formats, sizes, and contents.

Adding an attachment is pretty straightforward, but there are limitations, especially when it comes to email campaigns. Which is why we’ve created this short guide to explain the do’s and don’ts of attachments in emails.

The element of trust: email attachments may seem suspicious

Attachments are often used by marketers when writing a professional email as a way to give more value to the message and incentivize the user to open an email. If you are trying to reach out to a specific prospect and use attachments as a sort of personalization method, it might work.

But when we are dealing with cold emailing, including anything else besides the actual text content can seem shady.  This may sound obvious, but many marketers forget that when the recipient receives a message with an attachment from an unfamiliar source, they are likely to believe it’s malware.

Cold email isn’t a bad thing per se, but attaching a file to it makes it look far more suspicious and makes it more complicated for emails to avoid spam filters. This can put your email in the spam folder or worse, labeled by the ISP or mail client, inevitably hurting your sender’s reputation and harming your future email campaigns.

Moreover, many people ask “Should you explain attachments in business emails?” The answer is a resounding “yes”, of course. Explaining the attachment makes it a bit more trustworthy. This is why you should try not to send an email message that contains an attachment only – it doesn’t look professional at all and doesn’t raise any trust.

IP or domain reputation: attachments have a negative impact

Once again, using attachments in cold emails can throw a wrench in your campaign. Bulk cold emailing using attachments is likely to result in a high number of complaints. Every domain on the web is identified by ISP before it’s processed, allowing to block pirate content or adult web pages through the labeling of domains and IPs. A high complaint rate can catch your ISP’s attention.

In our case, the IP or email address you use for cold emailing can be flagged by ISP, and your email messages will either end up in the spam folder or completely blocked.

Therefore, email attachments in cold emails can lead to the deletion of your email domain name from a list of reputable sources. Use them only in small personalized email campaigns or with your existing clients.

Attachment formats: a wrong format can lead to an email block

So you’ve decided to use an attachment for your campaign email. You need to make sure people will feel confident and interested enough to open it. First of all, your email message in itself must convince the receiver to open/download the email attachment. If that’s not a problem, be mindful of this one rule.

Never send anything besides documents or images. In most cases, the user will never download anything besides a clearly visible document or image. It’s best to keep your attachments in .txt, .jpg, .gif, and.pdf formats.

PDFs make a great addition to any nurturing email, but they can be difficult to create and edit. You can find out how to edit a PDF easily from our friends at JotForm.

If you still need to send a file in a different format, make sure you are using an acceptable email attachment format because every ESP has its limits on file formats (for example, look through at Gmail attachment limits).

Size limits: follow email attachment limits for good deliverability

Want advice on the size of email attachments? Email servers and clients have email sending limits, so make sure you follow them. Moreover, email clients may reject your email as a whole because of its size. Try to keep your email message body within 15-100kb, with files no bigger than 10mb.

If you need to send a bigger file, it’s safer and generally more acceptable to attach a link to the file on Google Drive. Besides hosting large files, Drive will check the file for malware, solving the trust issue.

The email attachment size limits described above are considered universal if you don’t want to get caught in a spam filter.

Conclusion

While email attachments are a usual sight for marketing emails, there are certain rules you have to follow to keep your email deliverability high. If you’ve already taken care of your sender reputation and always use an email checker to clean your lists before sending, the main characteristic you still have to pay attention to is the attachment size limit – the smaller the file, the higher your chances to get into the recipient’s inbox.

Try to avoid sending files to cold leads: your email can be deleted or reported if there’s no established relationship between you and the recipient.