Below is one of the July satellite images, showing many of Russia's fighters lined up.
Since 2015, Russian airstrikes in Syria have taken out many ISIS fighters — although their numbers are often exaggerated — but they have also killed thousands of civilians.
The Syrian Observatory for Human Rights reported that between September 2015 and March 2016 alone, Russian airstrikes had killed about 5,800 civilians.
Since at least April, Syria's Idlib province as well as the city of Deir ez-Zor have been hit badly
A number of monitoring groups have even accused Russia of deliberately targeting hospitals and civilians, but Moscow barely acknowledges the civilian deaths and often denies it.
US-led coalition air strikes have killed many civilians too. The US often admits to responsibility in those deaths, though its figures are often smaller than what monitoring groups report.
Monitoring group Airwars reported in July that US-led coalition airstrikes had killed at least 4,354 Syrian civilians between August 2014 and May 2017, but the US-led coalition only admitted to about 600.
9. IL-20 "Coot"
The Coot "is equipped with a wide array of antennas, IR (Infrared) and Optical sensors, a SLAR (Side-Looking Airborne Radar) and satellite communication equipment for real-time data sharing," according to The Aviationist.
It's one of Russia's most sophisticated spy planes.
8. A-50U
The July satellite images showed one A-50U mainstay.
The A-50U is basically a "giant flying data-processing center" used to detect and track" a number of aerial (fighter jets, bombers, ballistic and cruise missiles), ground (tank columns) and surface (above-water vessels) targets," according to Sputnik, a Russian state-owned media outlet.
7. Su-35S
The July satellite images showed six Su-35S Flanker-E fighters.
The Flanker first deployed to Syria in January 2016 and is one of Russia's most advanced fighters, able to hit targets on the ground and in the air without any air support.
This shows Russian airmen installing precision-guided KAB-500s at the Hmeimim air base. One airman is removing the red cap that protects the sensor during storage and installation. The white ordnance is an air-to-air missile.
The video below shows a Fullback dropping one of its KAB-500s in Syria in 2015:
Source: Sim Tack, chief military analyst at Force Analysis.
The picture shows a Russian airman checking a KAB-1500 cluster bomb on an Su-34 in Syria in 2015.
Source: Sim Tack, chief military analyst at Force Analysis.
6. Su-34
The July satellite images showed six Su-34 Fullbacks.
The Fullback, which first deployed to Syria in September 2015, was Russia's most advanced fighter in the war-torn country for over a year.
It carries short-range R-73 and long-range radar-guided R-77 air-to-air missiles. It also carries Kh-59ME, Kh-31A, Kh-31P, Kh-29T, Kh-29L, and S-25LD air-to-ground missiles.
5. Su-30SM
The satellite images from July showed four Su-30SMs.
The Su-30SM, a versatile multirole fighter that's based off the Su-27, carries a variety of air-to-air and air-to-surface missiles and laser-guided bombs.
4. MiG-29SMT
Moscow sent an unknown number of Mig-29SMT Fulcrums to Syria for the first time in September, so they were not seen in the satellite images from July.
The upgraded Fulcrum is able to carry a variety of air-to-air and air-to-surface missiles as well as laser-guided bombs.
The video below shows the Mig-29SMTs in Syria for the first time.
3. Su-27SM3
The satellite images from July showed three Su-27SM3 Flankers, which were first sent to Syria in November 2015.
The upgraded Flankers, which are versatile multirole fighters, were deployed to the war-torn country to provide escort for its other attack aircraft, among other tasks.
This shows a Russian airmen fixing a RBK-500 cluster bomb to an Su-25 in Syria in 2015.
Source: Sim Tack, chief military analyst at Force Analysis.
This photo, taken near the Hmeimim air base in 2015, shows an Su-25 carrying OFAB-250s, which are high-explosive fragmentation bombs.
Source: Sim Tack, chief military analyst at Force Analysis.
2. Su-25
The July satellite images showed three Su-25 Frogfoots.
The Frogfoot is another of Russia's older attack aircraft. It's designed to make low-flying attack runs and is comparable to the US's legendary A-10 Warthog.
Su-25s had flown more than 1,600 sorties and dropped more than 6,000 bombs by March 2016, just six months after their arrival in Syria.
1. Su-24
The satellite images from July showed 11 Su-24 Fencers, but that number might now be 10, since one Fencer crashed last week, killing both pilots.
The Su-24 is one of Russia's older aircraft and will eventually be replaced by the Su-34, but it can still carry air-to-air and air-to-surface missiles, as well as laser-guided bombs.