I think the brown one underthe barking one is a pit... but I'm horrible at it... all I know is, the bottom one's a boxer.
A dog isn't attomatically vicious to everything just because it attacked a small breed.
1.) Could have been prey drive. Small dogs often look and act like prey... prey drive is not aggression.
2.) Dog aggression is very different from other forms of aggression. There are inumerable triggers that can be tripped between two dogs when they first see each other. For instance, akitas are often attacked by other dogs because of their dominant appearence (proud stature, errect ears, tail held high).
Although I agree that the dog should have been leashed and under control.
To everyone who thinks pitties are vicious, you may want to read the results of this temperment test:
http://www.atts.org/
Some of the results of the temperment test, number of dogs the passed, failed, and the percent that passed compaired to the ammount tested:
APBT
# Passed : 391
# Failed : 78
% That Passed : 83.4%
Am Staff
# Passed : 400
# Failed : 80
% That Passed : 83.3%
Cardigan Welsh Corgi
# Passed : 43
# Failed : 13
% That Passed : 78.6%
Collie
# Passed : 625
# Failed : 166
% That Passed : 79%
Doberman
# Passed: 1070
# Failed: 329
% That Passed: 76.5%
GSDs:
# Passed: 2250
# Failed: 467
% That Passed: 82.8%
Golden Retriever
# Passed: 551
# Failed: 108
% That Passed: 83.6%
Labs:
# Passed: 587
# Failed: 57
% That Passed: 91.1%
Shelties:
# Passed: 309
# Failed: 153
% That Passed: 66.7%
Staffie:
# Passed: 55
# Failed: 4
% That Passed: 93.2%
Now, I won't say they did the best... but most certainly better than some of the so called "safe" breeds like corgies and collies. I know you all love facts and statistics, so, here they are

.