Nuke Image is a nice and tiny addon for Phoenix:
Right click on an image, and have an option to "Remove this image". Sets the image's "display" style to "none", making it effectively disappear. Will not remove the whitespace if the image is inside an iframe or div with a fixed size.
Useful for hiding those epilepsy-inducing banner ads, or huge ads that make articles hard to read, or page-widening images
Works great for the ads that Mozilla's built-in ad blocker can't block yet. And also very useful if you want to print a page, but do not want to print the large ink-reducing header images some not-so-printer-friendly pages some sites have.
I've noticed that page doesn't load the proper download links if you view it with Mozilla. Or if it does the extensions refuse to install when you click on them. Do you know if any of these extensions are available for the parent browser? I've been searching through mozilla.org and mozdev.org without success.
Nuke Image also works on text elements, if you don't right-click on the text itself but rather the container around it (P/DIVs, I guess?) Also handy for printing purposes, even if the functionality was unintended.
nice, I've used the DOM Inspector sidebar for similar purpose (removing the extra space/ads on a page before printing them)