iTe tries to deal with large, included eps-files gracefully. Files bigger than 200kb (this is the default for the variable eps-limit and can be customized) are only displayed by their bounding box. You can toggle between bounding box and full display using a bound key.
Alternatively, you can create low resolution eps-files and include these instead. For example, if figure.eps is huge, and figure.s.eps is its low resolution pendant, then you could use
\DeclareGraphicsExtensions{.s.eps,.eps}
\includegraphics{figure}
while using iTe interactively, but uncommenting the first line for printing.