[elorant]

In my experience the better the picture(s) the higher the open rate. That is why art related newsletters have the highest open rate numbers. I worked at an art gallery once and we had a phenomenal 12% open rate for our emails which were purely informative.

Other than that, you should consider the option of clearing your recipient list every once a while. People who haven't opened a single email in a course of a year (or less) should be removed.

One trick that some e-commerce sites do is to send different emails to users depending on their purchasing history. Depending on your industry this may or may not apply.

[WA]

I think you have some bias here. Of course, an art newsletter that says "look at this picture" will have a higher open rate, because open rates usually are measured through remote-loading images from a tracking server. In most other emails, there is no need to load remote images. This doesn't tell you anything about actual open rates.

[stewfortier]

While I don't know what baseline you're comparing it to, 12% does not seem like a high open rate.

In my experience, cold sales emails should hover around 20-30%, so opted-in lists should at least perform on par with that.

Exceptional newsletters like The Hustle average ~50% opens (with over one million subscribers).

Also, you have to be careful with your image to text ratio.

Excessive images are often not helpful for deliverability as spammers have historically tried to embed images with spam text (where it's more difficult for the ESP to parse) versus actually including it as body text.

[foreigner]

But the recipient can't see the picture until after they've already decided to open the email?