Improving performance with static themes

In order to accommodate various screen resolutions and header heights, themes (formerly Personas) require very large image files. Header images need to be 3000 x 200 px and footer images 3000 x 100 px. As a result, loading them slows down Firefox. Animated themes pose an even more persistent problem for performance, because animated images are much larger in size, and the browser needs to redraw them continuously.

Bug 650968 was filed to address this issue, and the solution was to crop the images to your screen size when you start Firefox. Because smaller images are loaded when the browser starts, load times are much improved. However, a side-effect of the cropping is that animated images are not taken into account. For this reason, animated themes will no longer animate starting in Firefox 18. Since this was a unintended consequence, there are some edge cases where the image will animate normally until Firefox is restarted.

We understand that animated themes are very popular with some users, and people will be upset with this difficult decision. However, to keep Firefox performing optimally for the even greater number of users who care about speed, the decision was necessary. We would love to find a way to preserve animated themes, and are currently looking into alternative solutions. In the meantime, a workaround would be to install the Personas Shuffler, which will refresh your animated themes every time Firefox loads, keeping them animating continuously.

There are still many beautiful and creative themes available to personalize your Firefox, with more added every day, and we hope you continue to enjoy them.

12 comments on “Improving performance with static themes”

  1. Sailfish wrote on

    It would have been nice to have a pref setting to ignore the cropping so that those of us who have plenty of horsepower and enjoy certain animated themes would still be able to do so.

  2. wat wrote on

    I didn’t even know that something like animated Personas existed, so I don’t mind. But what about Australis???? Come on, guys…

    1. Relo wrote on

      Australis will be available on Windows in FF 20, later on Linux & OSX.

  3. rfh wrote on

    I am upset…Just get your brains together and apply what Sailfish suggests:
    Have a pref setting to ignore the cropping so that those of us who have plenty of horsepower and enjoy certain animated themes would still be able to do so.

  4. olexijl wrote on

    Just make a pref. setting to disable/enable animation of the themes. Or FF17 would be my last FF.
    Or do this setting in about:config

    1. Ferdinand wrote on

      Great strategy threatening the people you want something from.

      1. olexijl wrote on

        If you mean me, i fill really sad. It would be better solution, if more people would buy SSD drives (like me) and install the system there.

        Using SSD, i do not need much “speed”. I do care merely about functionality and security. So if Mozilla drops functionality for more speed, it is worse scenario.

        People who want speed should either use nonanimated themes or default theme anyway.

        I just wanna have a setting in about:config to disable/enable the feature.

  5. BrianZ wrote on

    Part 1:

    The referenced bug cites a “delay” of about 100 milliseconds when using a persona, and that’s only during startup, but this was perceived as some big problem that required cropping of persona images? That’s absurd! People routinely experience delays much longer than that when loading web pages from various sites. Moreover, if it’s not worth the virtually imperceptible wait to use a beautiful persona, then people don’t have to use them. I believe it’s only perceptible to programmers whose sole purpose in life seems to be to look for and measure such things and then obsess about how they can make things faster at any cost, as if that were the holy grail of their existence. If such a small delay causes such a concern, then I can only imagine the kind of conniption fits that an animated persona must cause to a programmer, given that they can indeed be very taxing upon system resources. However, I have to disagree that all animated personas are equally bad – not all redraw the screen continuously. If you don’t believe that, then check these out…

    These spend most of their time in a static state. Granted, most designers probably didn’t give any consideration to system resources and do redraw continuously, but they don’t have to be designed that way. Some required design rules could have been imposed if needed to allow any necessary breaks, though again, why does it matter if people don’t have a problem and want to them? Nobody is forcing them to use animated personas either. I suspect that programmers are more concerned about their own scorecard and being compared to the competition than what their users want.

  6. BrianZ wrote on

    Part 2:

    I also believe that many Mozilla staff neither understand nor care about people being concerned and upset about what they did, or else they would have put forth more effort into finding a solution rather than closing the bug with a “won’t fix” “resolution”. I don’t think it was a difficult decision for them at all, and I think they failed to consider just how many manhours or years were spent developing what could be tossed out. I also don’t believe their actions were necessary, because for those users who care most about speed, they shouldn’t be using personas anyway, let alone animated ones. You can have features or you can have speed, or you can have some mix inbetween, but you can’t have everything and that’s just they way things are – everything in life is a tradeoff. It’s just unfortunate that programmers are willing to tradeoff what users want in order to satisfy their own need for speed.

    I would like to believe that Mozilla would love to find a way to preserve animated themes, but I don’t, sorry. Unfortunately, all that I’ve read in bug #819190 says otherwise.

    I’m also wondering what ever happened with the support for scaleable vector graphics that Mozilla added to Firefox quite a while ago. A couple of years ago, there had been talk of the possibility of personas being able to make use of that technology for animations, and even the possibility of interactive animated personas, but has anything been done with that and could it provide any greater browser efficiency for persona animations than the current raster-based image animations?

    1. Amy Tsay wrote on

      As I said in the forums, people with the bandwidth to handle animated themes still have the option to use them. The Persona Shuffler work-around won’t be necessary until Firefox 18, and by the time goes into effect, we will likely have another add-on ready that will allow people to keep using animated themes.

      1. Cha wrote on

        Dear Amy,
        So where is that “add-on that will allow people to keep using animated themes”?
        I hate the Persona Shuffler! I don’t want to shuffle between my themes (who wants to see Halloween or Christmas Themes in February???) – and I don’t want to uninstall all themes except for one as a workaround either!!!

        1. Tom V. wrote on

          Many hundreds of hours have been spent creating animated Personas. This “solution” to a virtually non-existent problem is a slap in the face to all of us who have donated our time to making Firefox more customizable.
          I submit that a simple disclaimer stating that if a user chooses to use an animated persona, it is possible that the user may experience a slight loss in performance depending on the intensity of the animation and whether the animation was properly optimized. Leave the decision to the user.
          Three hundred kb is insanely small to refer to Personas as “very large image files”. It simply is not true. I frequently work with files that are nearly a hundred times that size.
          Animations need to stay under the 300 kb limit as well so I don’t understand this statement that “animated images are much larger in size”.
          Persona use has decreased severely since the advent of the GUI which placed the tabs on top. Many people simply stopped using Personas rather than try to configure their GUI to display them properly.
          You have the statistics on the number of downloads for Personas. The drop in the last two years or so has been dramatic. People whose images were numbering over a million downloads have seen losses of perhaps 90% since the change.
          Crippling the many exquisite animated Personas will only make things worse for the customization of Firefox and I’m sure will have a negative effect on the number of people using Firefox over some other browser.
          I don’t expect action at this late stage in the game but I felt the need to have my say.
          Anyone may email me at