Community talk ⇒ dvipng generated image is very big, how to make the picture smaller

[xiaohuihuiorg]

When use latex to compile .tex file and dvipng to convert .dvi file to get png image, for simple formula, the generated image is very big, is there any way to make the picture beautiful and smaller?
The command I used is :latex Template.tex and dvipng -D 600 -T tight Template.dvi -o x1.png
The resulting image is so big:
latex:\[ \sum {{{ \mathord{ \buildrel{ \lower3pt \hbox{$ \scriptscriptstyle \rightharpoonup$}} \over F} }_i}} = \frac{{d \mathord{ \buildrel{ \lower3pt \hbox{$ \scriptscriptstyle \rightharpoonup$}} \over v} }}{{dt}} = 0 \]
png:

[Johannes_B]

Welcome to the LaTeX community.
Please do not repost the same question over and over.

It is already in the right place and people reading here are seeing it. You will get an answer once a user can help you.

Johannes