How to vertically center text with an image in the same row of a table

The baseline of an image is at the bottom. You could use \raisebox to shift it up. Use half of \height, which stands for the height of the box to be raised.

\raisebox{-.5\height}{\includegraphics{some_picture}}

For example:

\documentclass{article}
\usepackage{mwe}
\begin{document}
\begin{tabular}{lll}
\raisebox{-.5\height}{\includegraphics[scale=0.25]{example-image}} & text & text\\
\end{tabular}
\end{document}

yields:

The new graphbox package introduces a new (vertical) align key which can be used in \includegraphics options. Using it there's no need for \raisebox, \parbox or taking care of distinguishing between c or m columns in tabulars.

\documentclass{article}
\usepackage{mwe}
\usepackage{graphbox} %loads graphicx package
\begin{document}
\begin{tabular}{ccc}
text & \includegraphics[scale=0.25]{example-image} & text\\
text & \includegraphics[align=c,scale=0.25]{example-image} & text\\
text & \includegraphics[align=t,scale=0.25]{example-image} & text\\
\end{tabular}
\end{document}

As egreg reminded me, adjustbox package provides a similar funcionality. Loading it with export option, a new key valign={t|m|b|T|M|B} can be used as \includegraphics option.

\documentclass{article}
\usepackage{mwe}
\usepackage[export]{adjustbox}
\begin{document}
\begin{tabular}{ccc}
text & \includegraphics[valign=m,scale=0.25]{example-image} & text \\
\end{tabular}
\end{document}

use the m column type for the image, eg:

\begin{tabular}{c m{4cm}}