Venezuela has blocked images on Twitter, the company says, offering a workaround for users who want to get tweets via text message on their mobile phones.
Company spokesman Nu Wexler said on Friday via email that "Twitter images are currently blocked in Venezuela".
Venezuela's main telecommunications company, CANTV, is government-run and handles the overwhelming majority of internet traffic.
Users said the blockage had ended by Friday and was most intense on Thursday, a day after two students were killed by gunfire during protests.
Video and still images that circulated via Twitter after the killings purported to show police and pro-government activists shooting at protesters.
The images' authenticity could not be confirmed.
Media coverage of the protests was limited, as Venezuela's government dominates the country's airwaves.