Twitpic has provided an excellent service for posting pictures on Twitter. Unfortunately, it has changed an important feature without telling its users: Twitpic will no longer show a full-size image. No matter how big the picture you upload, Twitpic reduces it to 600 pixels across.
This is a major limitation if you share pages from magazines or brochures, or tweet infographics. Text may be unreadable at 600px.
Twitpic support told me: "we've found that the majority of our users do not use the full size image and to conserve resources and keep Twitpic a free service, all images are being resized to 600px."
This doesn't make much sense. Users have to click the "View full size" button to see an image full size, and if they don't, few extra resources are used. (And if they do it, Twitpic gets to show them ads.) In any case, the smart way to conserve resources would be to limit the size of the file, not the size of the image. Twitpic allows images up to 10MB, so multi-megabyte gifs and videos are likely to consume a lot more resources than still images.
I have suggested that Twitpic limit still images to a megabyte in size, and resize larger pictures to 1280 x 768 pixels. This would fill the average user's screen, and be better than some competitors. However, I've also been looking for an alternative service.
(1) Twitter shows thumbnails of Twitpic images under tweets on its website, so they are more likely to be viewed than images that open a new page. This eliminates Instagram and many other photo services.
(2) Twitpic keeps a running total of how many times an image has been viewed, which provides feedback. Twitter's own photo-sharing service, based on PhotoBucket, does not.
(3) Your Twitpic profile shows the last 20 images you have uploaded. Someone who comes to look at one image may look at several.
(4) It's easy to use.
(5) You can sign in using your Twitter account, so there's no password to remember.
There are two obvious alternatives, the first of which is Yfrog. This is not quite as easy to use, and in my experience, images don't download quite as quickly as they do from Twitpic. However, Yfrog images show up in Twitter, and it does keep a running total of views.
The main problem with Yfrog is that there doesn't seem to be a way to save a photo without tweeting it. This means you can't upload a handful of photos at once and tweet them later, as needed.
The second obvious alternative is our old friend Flickr, the popular photo-sharing website taken over by Yahoo. It may be a disadvantage that you cannot log in with a Twitter account, but you can log in with a Yahoo account, and surely almost every IT person has one of those.
Flickr photos show up inside Twitter, which is the main requirement. It also records the number of views, though not in the most obvious place. Visitors can view or download a larger image, if they can figure out how to select "View all sizes", and they can also see previous images in your photostream. Flickr's main drawback is that you can't download original images (not even your own) without paying for a pro account. However, the images are large enough for most purposes.
You can share Flickr photos to Twitter, Facebook, Pinterest and Tumblr by selecting the service you want from a drop-down menu. This is a quick way to get a shortened link to tweet, even if you elect to do that separately.
Anyone who runs company accounts on several social networks should probably be managing a Flickr account as well.
So why don't more people tweet pictures from Flickr?
I suspect that this is due to Flickr's origins as a site for storing and sharing personal photographs. Everything you upload is marked as your copyright, and you can apply whatever rights you want. This doesn't appeal to people who are simply sharing photos they have found online, and are making no claim to ownership. Of course, the reverse applies to companies sharing their own copyright images.
Tweeting from Microsoft's SkyDrive is another option, though Twitter users may not know how to access the full-sized image. Clicking on the photo in Twitter pops up a larger version but in degraded quality. The solution is to click on the photo's filename (in this case, W_Hotel-DSC_0296.JPG), which takes you from Twitter to SkyDrive, where you can select either View Original or Download.
Most people have Hotmail accounts -- or use the Hotmail-replacement, Outlook.com -- and this provides instant access to SkyDrive storage (and web-based Microsoft Office applications). The only drawback is that SkyDrive doesn't track the number of views, as far as I can see, so there's no way of telling whether an image is popular.
I uploaded the same photo to all four sites and then downloaded it to compare results. The original was 4288 x 2848 pixels (2.90MB). Twitpic reduced this to 600 x 398 pixels (73K), which is inadequate. Flickr reduced it to 1024 x 680 (360K), which is acceptable for viewing on screen. Both Yfrog and SkyDrive downloaded full-sized originals, though only SkyDrive kept the original filename.
I also uploaded my photo directly to Twitter. There isn't a download button, but I saved the large image and deleted Twitter's broken file extension (.jpg-large). It turned out to be 1024 x 680 (143K).
To sum up, Twitter provides a quick way of sharing photos that you don't own, don't want to track, don't need to keep online, and will never use on other social networks ... as long as you don't care too much about the image quality. Twitpic is still very good for sharing photos that are up to 600px wide, but not larger. Yfrog is a good substitute for Twitpic, but Flickr may be better, depending on your needs.
If you actually want to share original images via Twitter, SkyDrive is the best option. However, Yfrog works well enough, and counts views.