United Press International and Financial News Network today are expected to announce a new financial service that will deliver live video images and news-wire information to specially designed personal computers.

The new service, called UPI Financial Information Services Inc., will be aimed at professional stock-market traders.

The unique aspect of the venture is the delivery of programming via satellite to a desktop computer, said a source who had seen the technology in action. The venture makes use of "windows" -- individual screens within the computer's main screen -- to show a video picture simultaneously with stock-market data, analysts' reports and general-news information.

The service is designed to replace such electronic-data competitors as Dow Jones and Reuter, which offer text but do not have the capability to deliver images.

Washington-based UPI is owned by Infotechnology Inc., which also owns 47 percent of FNN, the financial cable TV network. In order to receive the service, a subscriber would need special hardware made by Shark Information Services Corp., which Infotechnology acquired last week for $16 million.

The venture's video programming will be produced especially for financial traders and will not be carried on FNN's existing cable stations. In addition to FNN's production capabilities, the service is expected to make use of a UPI-owned subscription-television service, called Institutional Research Network, which charges brokerages and other financial institutions $18,000 a year for financial programming.