Use the scale=1.5 option in the \includegraphics command to resize the image to 150% of its original size. That is, \includegraphics[width=50mm,scale=1.5]{method.eps}. You can use a different percentage if needed.
If I've correctly understood Muhammad's question, he wants to change either the width or the height only, without keeping the aspect ratio.
I think that with all the previous answers (expect Lanouar's) the aspect ratio is preserved. However, in Lanouar's answer, you need to provide both the desired width and height. If you only want to indicate one while keeping the other as in the original image you can do the following (e.g. to change the image to be 1cm wide and keep the original height):
If you plan to reuse the LaaTeX code it is a good idea to use something like \includegraphics[width=0.5\textwidth]{figureFile}. In this code the picture will be adjusted to the width of half of text horizontal space.
Please search in google. As per my experience when you face any problem related to LeTeX just in google only. It will take time, give you confidence and more learning about LeTeX .
\caption{\textbf{The seeding cost (in hundred) for different values of $k$ for a) Facebook, b) Slashdot, c) Wiki-Vote, d) Twitter, e) Random1, f) Random2 dataset.}}
\label{fig:cost}
%\vspace{-2.5em}
\end{figure*}
--- "figure*" will take whole to column
--- "figure" will limit the figure span in single column
--- [width=0.3\textwidth, keepaspectratio,angle=0] this will control the size of the figure, change the fraction to your desired one. say 0.25\textwidth, if do not wanna keep the aspect ration same, use "height = 0.5 cm" like setting. you can change the angular position as well.
Can anyone give me the code snippet for figure size in IEEE format regardless of original size ?or how to balance between original size and size in latex?
notice that, the changing of size has no relationship with the the quality of figure it self. Thats why your figure need to bee with good resolution before insert it in using Latex