The ToolCAP study aims to see if using ultrasound to look at the lungs when children have symptoms of a lung infection will safely allow doctors to improve how they treat those infections. The study will also look at if it's possible to improve how doctors decide which children need antibiotics. * Lung infections are the most common reason for children to go to the clinic/hospital. * Doctors usually give an antibiotic to every child with a lung infection. * Lung infections can be caused by 2 different types of germs - bacteria or viruses. * Antibiotics only work against bacteria and not against viruses. Lung infections caused by viruses don't need antibiotics as the body fights them by itself. * Lots of research now shows that only 1 in 4 children with a lung infection actually needs an antibiotic, as the rest only have a viral infection causing the symptoms. * This means that 3 in 4 children get an antibiotic when they don't need it. * Taking too many antibiotics can cause problems for children as it can cause diseases like diabetes or asthma. * Nowadays, due to too many people using too many antibiotics, experts are starting to worry that bacteria are starting to become resistant (stronger than the antibiotic). * Ultrasound of the lungs appears to be a way of safely looking at the lungs to see if there is an infection and may help doctors better decide who needs an antibiotic. This study includes children aged 2 months-12 years who come to the hospital with a lung infection. Children who are very unwell or who have already had 2 days of antibiotic treatment will not be allowed to be in the study.