To check to see if an image is in the correct color space (sRGB) - Open the file in Photoshop. Click "Edit" at the top and select "Assign Profile". You want to make sure the profile says sRGB IEC61966-2.1. If it says anything else, it is not in the correct color space (see below).
If the profile is incorrect as it is above, close that window and go back to "Edit" and click "Convert to Profile". Make sure the "Destination Space" Profile is set to sRGB IEC61966-2.1 Then click OK and you're good to go!