Khan has denied any wrongdoing and said the case was politically motivated.
From NA-53, Mr Khan had defeated former prime minister Shahid Khaqan Abbasi.
Pakistan went to polls on July 25 and the counting of votes began soon thereafter in the evening, which was marred by tedious counting and allegations of rigging by major political parties, including the PML-N and PPP.
The Election Commission of Pakistan (ECP) on Tuesday has issued notifications to newly-elected members of the national and provincial assemblies.
The ECP move comes a day after the former cricket hero was formally nominated as its candidate by the Pakistan Tehreek-e-Insaf (PTI) for the slot of prime minister.
The picture, which was posted on Khan's Instagram account, has already garnered over 14,000 likes with many people amused by the mix-up.
"We issued conditional notifications for the wins of several candidates, including Imran Khan".
Notification of victory from Islamabad was withheld for a case related to violation of election code of conduct against Mr Khan.
The PTI chief had been summoned by the accountability body on July 18, but had sought more time to appear due to his busy schedule for campaigning for the general election.
The election commission says the withholding of notifications will not affect the National Assembly's election of its next prime minister, speaker, and deputy speaker, expected next week.
The results of 14 other constituencies have not been specified for various reasons, Dawn news reported. A total of 270 National Assembly (NA) and 571 Provincial Assembly seats together comprised the total number. After his appearance at the NAB office, Imran Khan headed to a private hotel for provincial parliamentary body's meeting of his party.