The priority of Cache-Control:max-age and ETag - browser-cache

Question

I use AWS S3 bucket the save the image files. I add one metadata max-age=315360000 for each file.
The response headers of image file is as below. In the headers both Cache-Control:max-age=315360000 and etag is set.
Cache-Control:max-age=315360000
Date:Thu, 15 Sep 2016 11:03:31 GMT
ETag:"326ae27d85f6d847f819e19955c0f0aa"
Last-Modified:Tue, 06 Sep 2016 03:23:26 GMT
Server:AmazonS3
x-amz-id-2:O/kt/JoZ/hmxSXUWGvkVLudMs6H4MDk8vgS2hIuZvAgGKMdYJsqSiqx/PnpT5AGsJ6FH8O3MGb4=
x-amz-request-id:9289AFE7D3BACB96
x-amz-version-id:P7bZwWZ9PO4I__ZHzwk5tXeiaU6QLSWJ
Question 1: Which one has the highier priority to control the cache?
If the Cache-Control:max-age=315360000 has higher priotity, the response of the next request should be 200 from cache. If the ETag has higher priotity, the response of the next request should be 304.
I make the test on the Mac chrome (Version 53.0.2785.89 (64-bit)). I get a strange behavior.
Test 1 - access the image url to browser. The response is 304.
Test 2 - access an html file which contains the image element to
reference the image. The response is 200 from cache
I use the chrome dev tool to copy the the two requests as curl command lines.
Test 1 curl command lines
curl 'http://s3.cn-north-1.amazonaws.com.cn/xxxx/xxxx.jpg' -H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.89 Safari/537.36' -H 'Referer: http://pano.shejijia.com/?locale=zh-CN&data=http%3A%2F%2Fjuran-prod-contents.s3.cn-north-1.amazonaws.com.cn%2FAsset%2Fpanos%2F9b57a2b1-0ff7-4c79-ad3d-3343d95f2ad9%2F2702d299-c269-442f-804b-49d94296454e.json&mode=navipano&designId=9b57a2b1-0ff7-4c79-ad3d-3343d95f2ad9' -H 'Origin: http://pano.shejijia.com' --compressed
Test 2 curl command lines
curl 'http://s3.cn-north-1.amazonaws.com.cn/xxxx/xxxx.jpg' -H 'Accept-Encoding: gzip, deflate, sdch' -H 'Accept-Language: en-US,en;q=0.8,zh-CN;q=0.6,zh;q=0.4' -H 'Upgrade-Insecure-Requests: 1' -H 'User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_9_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.89 Safari/537.36' -H 'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8' -H 'Cache-Control: max-age=0' -H 'If-None-Match: "d88e24d354fc3b4b43530c0bfe338b01"' -H 'Connection: keep-alive' -H 'If-Modified-Since: Tue, 06 Sep 2016 05:54:16 GMT' --compressed
You can see chrome generates two different curl commands. I guess chrome explains the cache headers in different ways in the two cases.
Questions 2: Why chrome explains the cache headers in different ways in the two cases above?
Questions 3: How to make chrome uses a same manner to response the cache headers? Either one is ok.