How to handle Backup Images in HTML5 banner ads.




I have been given specs to build banners for Tubemogul / Adobe CC, and I am unclear on how backup images should be handled.

This has caused some confusion with developers, traffickers and producers, with no clear answer.


I build my HTML5 banners from scratch (No Adobe Animate, or GWD). That said, there is no clear guide on what to do for any platform.

After looking through the ad specs link below:

Ad Specs and Guidelines

I found this guide document:

Dropbox - HTML5 Zip Container Walkthrough.pdf

Media agencies, and clients have sent me several versions of the above PDF, which annoyingly has code snippets AS AN IMAGE, and sometimes has working links and sometimes it doesn't. However, the most frustrating part is the one on backup images which reads:

Caveat: Fallback images are not supported when using Ad Cloud to serve HTML5 display

creatives. To implement fallback images, you need to build them directly into your

HTML5 creative according to the HTML5 browser support matrix.

NOTE: while "HTM5 browser support matrix" underlined, it is not as a link ...however, on some versions of this document the link works, but just takes you to "". Which might as well be a link to the "".

My questions are:

  1. Should backup images be included separately to the HTML5 zip container, as has been industry standard for many years?
  2. OR, should a backup image be included in the HTML5 zip container, and referenced in the index.html?
  3. OR, should the HTML5 ad be built in such a way, so as to be supported by older browsers, without any backup image at all?

If the backup images need to be included in the HTML5 zip container, how should that be included?
Could you provide a code snippet of how you would like the image included to give maximum browser support. Or ideally, could please provide an example banner, which could be used as a build reference.

Thank you.

Accepted Solutions (1)

Accepted Solutions (1)




Hi Okostudio,

The backup image needs to be included in the Zip file itself.  You need to include the backup image which would be called in the Index.html code. The backup image would appear in case HTML 5 creative fails to appear because of any reason.



Answers (4)

Answers (4)



Thank you Yusuf,

I noticed that in the example you sent through, there is no backup image.

  • When you submit this for trafficking, would you send a .zip files, and a separate jpg/gif backup image?
  • If not, how do you supply a backup image?

Also, the Guide you sent through is the same document I linked, in the initial question, which is unclear on what to do with backup images.




Hey Okostudio,

To answer your question, the backup image be included in the HTML5 zip container, and referenced in the index.html.

The index.html file should call the back up image file and the image file should be uploaded under the zip file.

i have attached step by step guide of the HTML5 Creative we use in Ad Cloud and also a zip file for one of my client who are currently using HTML 5 Creative.

Here you go with the Guide link and an example of HTML5 Creative which is currently being used to understand the current guidelines.

HTMLGuide :

Guide -

Example :

Example -

Hope it helps !!





Thanks Wesley,

Unfortunately, under the Display section of the Updated Ad Specs PDF you provided, there is a link to the same document I have mentioned in my first post: "dropbox HTML5 Zip Container Walkthrough.pdf".