Ever since the day it was published, the What Size Banners Should an Affiliate Program Have? post has been one of the most frequently demanded ones in my blog. However, while I did cover the most popular banner sizes in it, I made no mention of the banner file size at all.

Surprisingly, most major affiliate networks make no recommendations on the maximum recommended banner file size. The first network that I have seen make such a recommendation is LinkConnector. They advise that advertisers’/merchants’ banner sizes do not exceed 30 KB. Now, in reality, their “advice” is much more than one. It’s actually a restriction. You cannot upload a banner that’s larger than 30 KB while setting up your affiliate program with them. While, imposing such restrictions may not be a very good idea (30 KB is not much for larger skyscrapers and leaderboards, especially if we want them to be of high quality), advising merchants on the file size is actually a very good idea. It helps everyone who is involved in the affiliate marketing channel: affiliates who are using the banners, networks who are hosting them, merchants who risk being less promoted when/if their files are too bulky.

Over the past two weeks I have been polling my blog’s readers on this subject, and while so far the response hasn’t been too overwhelming (to put it mildly), it does look like that 30 KB limit is right around the comfort level mark for online publishers:

Conclusion: by all means, do everything possible for your banner file sizes not to exceed 30 KB/each. If one does have to be larger than that, 60 KB is the next threshold that you want to keep in mind. It’s easy to remember 30 * 2 = 60.

Banner file size is not a small issue. Knowing what’s preferred should help merchants build more affiliate-friendly affiliate programs. If you haven’t yet expressed your opinion in the above-quoted poll, I would highly appreciate you voicing your opinion out by casing a vote, and/or posting your comment below.

This is a very important question regardless of whether you are going to market products or services through the affiliate channel. If it is the former, you will pay a lot of attention to deep-linked text links, conveniently formatted and well-categorized data feed, but you will have to have both general banners and holiday-specific ones. If, on the other hand, you’re providing a service (and you will have no data feed at all), you definitely need a good creative inventory for affiliates to work with. One or the other, you want to provide your affiliates with a solid and diverse creative arsenal.

Below you may find a list of banner sizes that I recommend every affiliate program to have. The list follows this format: [banner size] – [minimum quantity]-[recommended quantity]. Some of these recommendations come from my observations of the sizes that affiliates prefer (e.g.: 88×31 px buttons, the importance of having which you should never underestimate); while the choice of some other sizes rests directly on the assumption that many webmasters, who will be recruited into your affiliate program, are already monetizing their traffic using Google AdSense, and, therefore, it is important for you to provide them with a banner to upload in place of an AdSense unit (e.g.: 120×600 px and 160×600 px skyscrapers). Here is my list:

468×60 px – 2-5 banners
125×125 px – 2-5
120×600 px – 2-5
88×31 px button – 2-5

160×600 px – 2-3
120×240 px – 2-3
234×60 px – 2-3
254×331 px – 2-3
728×90 px – 2-3

720×300 px – 1-2
300×250 px – 1-2

Remembering that some affiliates will need banners of different sizes or color gamma, it is always good to let them know that you are open to creating custom banners for affiliates. If you do not have an in-house capability of handling the creative support, it is easy to outsource such work on the on-demand basis.

If you are an affiliate reading this post, and there’s a banner size that you think must be listed, but it’s not, feel free to post your recommendation in the “comments” field below.