Oscar Carlsson wrote:
It wasn't that long ago that everyone split big images into many smaller ones to make the page appear to load faster because there were many connections to the server.
That's correct, but for todays fast connections the HTTP overhead is higher than the transfer. And if there are many small files to transfer it makes sense to use CSS Sprites.
Is it a better solution to load images in the background while the user is typing in the login info, so that the images are cached by the time the "login" button is pushed ?
This is just for the first hit, instead you should set caching headers for static files so they remain on the client. BUT this is out of scope for Roundcube and should be set in Apache.
You can go as far as to include the raw image in the CSS if I remember correctly ;)
Does not work cross-browser, so no good idea.
If RC is used a lot by the user, won't the images reside in the local browser cache 90% of the time anyway ? Besides first-time users, will this change really make a difference ?
No, it won't, except the caching headers are set the wrong way.
Don't know if sprites will have an effect or not considering this.
I'm right now optimizing our companies homepage using Sprites and it's a lot of work and relatively complex, especially in terms of updates. For RC I don't think it's worth it as there are not too many images and the users are all returning users. For a commercial site where you have not returning visitors or visitors returning after their cache was cleaned it makes sense to spend the time on optimizing with CSS Sprites.
Spend your time on new features.
Mike