How I can make color transparent in Photoshop? For example, I have picture of smoke, and I want to make background color (which is black) transparent. How?
This fire image:    As you can see, it has a black background, which I can't delete (because it would probably destroy the smooth-looking fire effect). I want to place some fire in a photo.  However, I remember it was possible to take such images and do something in photoshop so that when you place them over a photo, the black is gone and the fire is perfectly blended there. But I can't remember what feature or option was it. Any ideas?  Photoshop CS5.
Where can I find out about Stack Overflow history? I'd like to know how Stack Overflow and other sites started - which was first, who initiated it (OK, that's on the link below) and why, how the different sites evolved, how the rules evolved, etc.  Where can I find such information?  Of course, I know I can look at  for a brief overview but I'm wondering if there is info on this site, particularly more detailed.. Bread and butter is/are my breakfast? Bread and butter (is or are) my breakfast?  And what's the difference between the above sentence and saying "My breakfast is bread and butter"?  Thanks. Cancellation of Direct Products Stacks for Unity Launcher I'm looking forward to emulate the behavior of OS X Dock Stacks so that I can have, for instance, one stack for browsers and another one for IDES. People at ask ubuntu are doing a lot of cleaver stuff with custom Launchers and Quicklists (see ). So has anyone figured out how to have stacks in Unity? Anything fancier than a static Quicklist over a dummy folder icon? Tight bound for $T(n) = T(n^{1/2}) + 1$ Is simply connectedness preserved after deleting a high codimension set Why is it “a defeated Napoleon, not “the defeated Napoleon” who rode off the battlefield and into exile? I noticed an infinite article; ‘a’ was used before ‘defeated Napoleon’ in the following sentence of Jeffery Archer’s novel, "Fales Impression" :  “General Sir Harry Wentworth sat at the right hand of the Iron Duke that night, and was commanding his left flank when a defeated Napoleon rode off the battlefield and into exile."  I’m curious to know why it should be “a defeated Napoleon,” not “the defeated Napoleon” or simply “defeated Napoleon.” Isn’t it only one Napoleon who was defeated the battle and exiled (to St. Helena). It looks like as though there were many (defeated) Napoleons who were exiled.  It’s always headache for me to handle articles as we Japanese (I think Chinese too) don’t have article as the basic part of speeches in our language system. I’ve studied it on English grammar text books at school, but have never reached full understanding of the usage of articles, because we don’t have that practice. Is there any special knack to master how to use articles? Does $\sum\limits_{n=1}^\infty\frac{1}{\sqrt{n}+\sqrt{n+1}}$ converge? Does the following series converge or diverge? $$ \sum\limits_{n=1}^\infty\frac{1}{\sqrt{n}+\sqrt{n+1}} $$ The methods I have at my disposal are geometric and harmonic series, comparison test, limit comparison test, and the ratio test. Why does energy have to be emitted in quanta? I was reading some popular science book and there was this sentence. It says that energy has to be emitted in discrete portions called quanta. Otherwise the whole energy in the universe would be converted into  high frequency waves.  I'm not a physicist, so this conclusion seems to me like a huge leap.  First, we assume that energy is emitted in a continuous way (not in quanta).  And how do we get to the statement "the whole energy in the universe would be converted into  high frequency waves"? sed substitution with Bash variables Homemade coconut milk separates into different layers after a day in the fridge I made some coconut milk. After a day in the fridge there was two layers of liquid in the jar, coconut water and solid coconut which I found out afterwards that it is called coconut butter! When I stir them together to  have my coconut milk back, it didn't work. Is there a way to prevent this? If not, is there a way to have coconut milk again? Correct interpretation of a "double-negative" in American Pop Culture (i.e. "I ain't afraid of no ghost!") I'm having trouble with \includegraphics I'm using MacTeX I know some countries such as UK has the steering wheels of their cars on the right side. But as we can see, most of the Europian countries uses it at the opposite side. Since I used to drive a car with left-steering wheel I found it impossible to drive a car with right-steer!  Not curiosity, but I am trying to map if this issue is related to User Experience or not. Travelling in Schengen area while waiting for permit of stay renewal in Italy This button is in the new Firefox, but what is the name of it? Beamer item balls go missing while compiling in XeLateX since yesterday's TeXlive update, however, the same code works with pdfLaTeX. Any solution, please. Here is my MWE: \documentclass{beamer}  \setbeamertemplate{itemize item}[ball] \setbeamertemplate{enumerate item}[ball]  \begin{document}  \begin{frame} \frametitle{A tested title} text \begin{enumerate}     \item this is an item \end{enumerate} text3 \begin{itemize}     \item this is an item \end{itemize} \end{frame} \end{document} Is it possible to search by posts that contain an image? Sometimes when going back through e.g. my previous answers to find some information, I know the question I am looking for contains an image, and I know the language tag, but I'm a little hazy on the other parameters.    Is there a search option to restrict results to only those posts that contain an image? Akin to filtering email to show only those with attachments I guess.  I see that with  you can filter by user, votes, answer count or whether a question has an accepted answer, or has been closed or migrated. But not images? Draft mode for pgfplots Any way to change my review of suggested edit? I goofed and rejected a suggested edit, a vote that was actually directed at the previous edit that I was reviewing. As this is unfair to the user who posted the suggested edit in question, is there any way in which to change/cancel my reject?