Letter and Image Sizes

SPAM filters, blacklists, sender reputation, trigger words --- all those phrases run through email marketers' minds when we think about email deliverability. While those are all critical factors that will impact deliverability, one aspect that is often overlooked is the email file size. The size of your email plays a significant role in whether your message makes it to the inbox and how it looks once it gets there.

There are many different (and contradictory) recommendations floating around the web for what the max is for email file size before it negatively effects your inbox placement.

Reports vary when it comes to email file size and deliverability. The V12 group says the overall file size of the email should not exceed 50 -70KB while Responsys recommends total email size be limited to 125KB.

One thing for sure, deliverability issues began to occur once the email file size was over 250KB. Every email from 110KB to 650KB wound up failing multiple SPAM filters.

The size of the email is made up of much calculations:

1. The size of the text itself.

2. The size of the HTML characters (the source code) which makes up the formatting of the letter.

3. The size of the images - and not just the size itself but the encoding which converts it from one digital format to email compatible format.

4. The size of any attachments.

Image Sizes

Some resources warned images that exceeded 20KB will get flagged as SPAM while others said images that are under 50KB are good to go. It is important to note that using overly large emails without any supporting text in your email can raise a red flag for SPAM filters. This is because spammers usually display information in large images instead of text because the filter programs cannot “read” the content. If you stick with a 60/40 text to image ratio, you should avoid having deliverability issues.

· Using a image converter, convert your images to PNG format. This is the smallest.

· Do not use GIF (especially animated GIFs) and do not use BMP format images!

· Try to keep your images as small as possible - even 50KB!

· People are using cell phones more, your images should not be more than 480 pixels wide.

· People are using wireless internet, the smaller the image and email the better.

Email Load Time

Large emails also affect load time. Emails with a slow load time are more likely to get deleted than light, small emails that display in a jiffy. Your readers are inundated with hundreds of emails a day so the chances that they’ll sit patiently and watch the rainbow wheel load is unlikely. It is also important to note that emails with a large file size load even slower on mobile than on web or desktop. Not to mention, larger images will eat up valuable megabytes in limited data plans. With about 20-50% reading email on mobile, we carefully design emails that will accommodate the limited data plans, slow networks, and various behaviors of the mobile email clients.

Test Your Letter

Send this letter to your iPhone or a friend's iPhone. Have them read it on their iPhone. Does it still look good, professional and correct? If not, do not send this letter and get it formatted properly. Contact your local marketing firm for help. This letter is an image about you and your property. If it looks junky, then your hotel can be viewed as junky.

The more professional, complete and proper your confirmation letters and scheduled letters look, the better you look! You may want to consult your marketing firm when creating your letters - this is probably the first image the guest will see with regards to your property!