How to export an image collection in GEE?

[mfai123]

I am a new student and have been trying to export images from GEE. The following code generates Mean Surface Soil Moisture for each month over the course of 6 years, and I can export the data as a table. How can I generate the images and export the images?

`// SMAP(Soil Moisture Active Passive)soil moisture data

// Extract & Visualize Monthly Time Series Analysis of SMAP soil moisture and export to your Google Drive as a CSV file

// 1. Define countries boundary
var Countries = ee.FeatureCollection('USDOS/LSIB_SIMPLE/2017');
var roi = Countries.filter(ee.Filter.eq('country_na', 'Afghanistan'));
Map.addLayer(roi, {}, "roi");
Map.centerObject(roi);

// 2. List of years
var years = ee.List.sequence(2016, 2021);
var months = ee.List.sequence(1, 12);

// 3. Load SMAP Data
var coll = ee.ImageCollection('NASA_USDA/HSL/SMAP10KM_soil_moisture').select('ssm');
print(coll.first());

// 4. Set visualization parameter
var soilVis = {
min: 0.0,
max: 28.0,
palette: ['0300ff', '418504', 'efff07', 'efff07', 'ff0303'],
};
// 5. Center and add SMAP layer
Map.centerObject(roi); // Zoom level ranges from 1 to 16
Map.addLayer(coll.mean().clip(roi), soilVis, 'Soil Moisture');

// 6. Summaries our SMAP (Soil Moisture Active Passive) soil moisture data by month and year
var smap = coll.select('ssm')
.map(function(img){
var d = ee.Date(ee.Number(img.get('system:time_start')));
var m = ee.Number(d.get('month'));
var y = ee.Number(d.get('year'));
return img.set({'month':m, 'year':y});
});
print(smap.first());

// 7. Function generate monthly soil moisture data for each year
var byYearMonth = ee.ImageCollection.fromImages(
years.map(function(y){
return months.map(function(m) {
return smap.filterMetadata('year', 'equals', y)
.filterMetadata('month', 'equals', m)
.select('ssm').mean()
.set('year', y)
.set('month', m)
.set('date', ee.Date.fromYMD(y,m,1));
});
}).flatten()
);
print("monthlyCol", byYearMonth.first());

// 8. Zonal statistics to sumarries SMAP soil moisture to specific study area (eg Afghanistan)
var smapAfghanistan = byYearMonth.map(function(img) {
var features = roi.map(function(f) {return f.set('date', img.get('date'), 'month', img.get('month'), 'year', img.get('year'))})
var proj = ee.Image(byYearMonth.first()).projection();
return img.reduceRegions(features, ee.Reducer.mean(), 1000, proj);
}).flatten();
print("SMAP Summary Mean", smapAfghanistan.limit(10));

// 9. Export the resulting mean soil moisture as a table to Google Drive
var selectors = "year, month, country_na, mean";
Export.table.toDrive({
collection: smapAfghanistan,
description: 'SMAP_Timeseries',
folder: 'earth_engine_data',
fileNamePrefix: 'SMAP_Timeseries',
fileFormat: 'CSV',
selectors: selectors
});`

From this point, I am unsure how to export the images (are images even generated? Is it correct to call 'smapAfghanistan'?). I tried the following, but it did not work:

`
var batch = require('users/fitoprincipe/geetools:batch');

// Set export folder (relative to Google Drive root folder)
var output_folder = 'gee-export';

// Export collection image to Drive
batch.Download.ImageCollection.toDrive(
smapAfghanistan,
output_folder,
{
name: 'name'
scale: 30,
maxPixels: 1e13,
region: roi,
type: 'int16'
}
);
`