Request Issue Failed with INVALID_ARGUMENT on Google Cloud Vision API - google-cloud-vision

Question

when executing, with a key that has worked in the past but that I haven't used for a few weeks, the following cURL
curl -v -k -s -H "Content-Type: application/json" https://vision.googleapis.com/v1/images:annotate?key=MyKey --data-binary #a.json
where a.json is
{"requests": [{"image": {"content": "SUkqADwmAAD////8gYEoGct1VHdGU..."}, "features": [{"type": "TEXT_DETECTION", "maxResults": 1}]}]}
returns
* Trying 173.194.205.239...
* Connected to vision.googleapis.com (173.194.205.239) port 443 (#0)
* TLS 1.2 connection using TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
* Server certificate: *.googleapis.com
* Server certificate: Google Internet Authority G2
* Server certificate: GeoTrust Global CA
> POST /v1/images:annotate?key=MyKey HTTP/1.1
> Host: vision.googleapis.com
> User-Agent: curl/7.43.0
> Accept: */*
> Content-Type: application/json
> Content-Length: 13454
> Expect: 100-continue
>
* Done waiting for 100-continue
* We are completely uploaded and fine
< HTTP/1.1 400 Bad Request
< Vary: X-Origin
< Vary: Referer
< Content-Type: application/json; charset=UTF-8
< Date: Wed, 10 Feb 2016 18:02:12 GMT
< Server: ESF
< Cache-Control: private
< X-XSS-Protection: 1; mode=block
< X-Frame-Options: SAMEORIGIN
< X-Content-Type-Options: nosniff
< Alternate-Protocol: 443:quic,p=1
< Alt-Svc: quic=":443"; ma=604800; v="30,29,28,27,26,25"
< Accept-Ranges: none
< Vary: Origin,Accept-Encoding
< Transfer-Encoding: chunked
<
{
"error": {
"code": 400,
"message": "Request Issue Failed.",
"status": "INVALID_ARGUMENT"
}
}
* Connection #0 to host vision.googleapis.com left intact

Answer 1

Version 1 of the Google Cloud Vision API (beta) does not permit TIFF [1]. Here is a list of the currently supported formats:
JPEG
PNG8
PNG24
GIF
Animated GIF (first frame only)
BMP
WEBP
RAW
ICO
[1] https://cloud.google.com/vision/docs/image-best-practices#image_types

Answer 2

Turns out this is because I was sending base64 encoded tif images. Works fine for PNGs. Pretty sure I was told this in the docs.