APEX: Image content from URL

file.cls

String extFileUrl = 'https://images.unsplash.com/photo-1592746455916-7ac99236b6d6?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=634&q=80';

Http h = new Http();
HttpRequest req = new HttpRequest();
// Replace any spaces in extFileUrl with %20
extFileUrl = extFileUrl.replace(' ', '%20');

// Set the end point URL
req.setEndpoint(extFileUrl);
req.setMethod('GET');
req.setHeader('Content-Type', 'application/' + fileContentType);
req.setCompressed(true);
req.setTimeout(60000);

// Now Send HTTP Request
HttpResponse res  = h.send(req);
System.debug('Response from Server: ' + res.getBody());

// getBodyAsBlob method was will convert the response into Blob
Blob fileBlob = res.getBodyAsBlob();