从array/json获取前端值

我想得到我的图像值，例如可以是images/thispicture.png。

我有一个带有一些值的Array或Json，但问题是我只想要数组中的图像。

这就是我现在从阵列中得到的：

{"image_intro":"images'/16748007940_1cc8f06622_small.jpg","float_intro":"","image_intro_alt":"","image_intro_caption":"","image_fulltext":"","float_fulltext":"","image_fulltext_alt":"","image_fulltext_caption":""}"><img src="/{"image_intro":"","float_intro":"","image_intro_alt":"","image_intro_caption":"","image_fulltext":"","float_fulltext":"","image_fulltext_alt":"","image_fulltext_caption":""}"><img src="/{"image_intro":"","float_intro":"","image_intro_alt":"","image_intro_caption":"","image_fulltext":"","float_fulltext":"","image_fulltext_alt":"","image_fulltext_caption":""}

我只想要"image_intro"，我该怎么做？

当我json_decode时，我得到这个输出：

["image_intro"]=>
  string(39) "images/16748007940_1cc8f06622_small.jpg"
  ["float_intro"]=>
  string(0) ""
  ["image_intro_alt"]=>
  string(0) ""
  ["image_intro_caption"]=>
  string(0) ""
  ["image_fulltext"]=>
  string(0) ""
  ["float_fulltext"]=>
  string(0) ""
  ["image_fulltext_alt"]=>
  string(0) ""
  ["image_fulltext_caption"]=>
  string(0) ""

该怎么办？我怎么能把它变成一个字符串，我只是可以回声出来？

提前感谢！