Post reporter Ben Terris inadvertently kicked up a firestorm on Wednesday when he tweeted a screenshot of a page from the Web site for CPAC, the Conservative Political Action Conference that kicks off this week.

Terris expected to see an image of Ben Carson. Instead, he saw an image of Sen. Tim Scott (R-S.C.). (Both, as you probably know, are African American.)

Because such things tend to attract interest on the Internet, the tweet attracted interest on the internet. The liberal blog Talking Points Memo wrote a quick story about it, for example. By the time TPM went to the site, though, the image associated with Carson's name was the correct one.

Scott, for his part, seemed amused. He (or whoever operates his Twitter account) replied to Terris, noting that a similar mistake had been made in the past.

Fine. Mistake made; mistake fixed. Except: Not quite.

When contacted by TPM, CPAC spokesman Ross Hemminger told the site that the image was "a Photoshop," and that he'd "spoken with the web people who verified that it was definitely photoshopped." Terris rebutted the claim to TPM ("I don't know anything about Photoshop, anything about web design") and on his Twitter account.

When we reached him by phone, Terris explained exactly what he was doing this morning. (Probably unneeded disclosure: Terris and I know each other through The Post.) He was thorough. "I woke up," he began, and explained that he was trying to find someone to shadow at the conference, and knew Carson's people. To find Carson's schedule: "I Googled CPAC on my phone. I clicked on the link. I saw the list of speakers -- I think I was on the list of speakers page? [Ed. - Here. It's not actually in the mobile app.] I scrolled down to Ben Carson. Saw Tim Scott's photo there."

And then he took a screenshot. Except he didn't know how, so he figured out the proper combination (on an iPhone 6, like his, it's the power button and the home button at the same time). He took a few screenshots, including the one at right.

Unlike Terris, I do happen to know about Photoshop and Web design, having worked for a time as a senior designer at Adobe, the makers of the software. And there are flags that make it clear that the image wasn't altered.

Photoshopping is harder than it seems. It's not the sort of click-button-to-change-image magic you see on "CSI." And it gets particularly tricky to do it when changing the image causes other things on the page to change.

Like the text. Below is Terris's original image and an image of the existing page that I took from my phone. Notice that Carson's photo is longer than Scott's. It's still the full image of Scott, as you can see here. It's just shorter. But that shorter image means that the text flows under the photo one line higher.

See the text under the red line? If Terris (or someone) is Photoshopping this, they need to move all of the text so that the line breaks work evenly with the shorter photo as well. And it would need to reflow all of the text with new line breaks all the way down. That is far trickier than simply swapping out the photo. Not impossible. But not as easy as it seems.

So what happened? CPAC, responding to Terris's initial tweet, pointed to the Google cache of the speaker page, showing that the search engine had captured a version of Carson's speaker page with the proper image at some point earlier. But that was using a desktop browser. It's possible that this was a short-term bug that only affected those trying to access the site with a phone. Web sites usually create separate formatting for mobile devices and desktops, and at least one other user, unaffiliated with The Post or CPAC, saw similar problems from a phone.

We spoke by phone with Ian Walters, CPAC's communications director. "When we entered it in, we entered Senator Scott's photo with Senator Scott's bio," he said. "When we put in Ben Carson, we put in Ben Carson's photo with Ben Carson's bio." He pointed out that there's enough fakery out there on Twitter that it's worth being skeptical. Still, Walters said: "It does not appear that Ben was sitting in his bed and Photoshopping this."

Someone from CPAC had called Terris earlier Wednesday, too. "Look," Terris says he told that person, who was trying to explain the technical reasons it couldn't have happened, "I literally don't know how to refute anything you're saying, because I don't know how the Internet is made. I just took a photo and tweeted it."

He also confirmed that he doesn't know how to use Photoshop. Based on our conversation, I believe him.