You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allimages aicontinue="20150504024149|SPDX-2.0.docx" />
  </query-continue>
  <query>
    <allimages>
      <img name="Spdx-spec.zip" timestamp="2019-06-04T12:33:14Z" user="JackM" url="https://wiki.spdx.org/images/Spdx-spec.zip" descriptionurl="https://wiki.spdx.org/view/File:Spdx-spec.zip" ns="6" title="File:Spdx-spec.zip" />
      <img name="SPDX-2.2.jpg" timestamp="2018-11-27T19:00:14Z" user="Goneall" url="https://wiki.spdx.org/images/SPDX-2.2.jpg" descriptionurl="https://wiki.spdx.org/view/File:SPDX-2.2.jpg" ns="6" title="File:SPDX-2.2.jpg" />
      <img name="GSOC_2018_-SPDX_Add_Licenses-Galo_Castillo.pdf" timestamp="2018-05-17T17:22:01Z" user="Jlovejoy" url="https://wiki.spdx.org/images/GSOC_2018_-SPDX_Add_Licenses-Galo_Castillo.pdf" descriptionurl="https://wiki.spdx.org/view/File:GSOC_2018_-SPDX_Add_Licenses-Galo_Castillo.pdf" ns="6" title="File:GSOC 2018 -SPDX Add Licenses-Galo Castillo.pdf" />
      <img name="2018_SPDX_Ecosystem_Overview.pdf" timestamp="2018-04-05T19:06:35Z" user="Podence" url="https://wiki.spdx.org/images/2018_SPDX_Ecosystem_Overview.pdf" descriptionurl="https://wiki.spdx.org/view/File:2018_SPDX_Ecosystem_Overview.pdf" ns="6" title="File:2018 SPDX Ecosystem Overview.pdf" />
      <img name="SPDXSpreadsheetTemplate-v2.1.xlsx" timestamp="2017-10-17T05:50:28Z" user="Goneall" url="https://wiki.spdx.org/images/SPDXSpreadsheetTemplate-v2.1.xlsx" descriptionurl="https://wiki.spdx.org/view/File:SPDXSpreadsheetTemplate-v2.1.xlsx" ns="6" title="File:SPDXSpreadsheetTemplate-v2.1.xlsx" />
      <img name="Specification21.png" timestamp="2016-10-26T13:56:43Z" user="JackM" url="https://wiki.spdx.org/images/Specification21.png" descriptionurl="https://wiki.spdx.org/view/File:Specification21.png" ns="6" title="File:Specification21.png" />
      <img name="Logo_spdx_250.png" timestamp="2016-10-21T12:34:57Z" user="JackM" url="https://wiki.spdx.org/images/Logo_spdx_250.png" descriptionurl="https://wiki.spdx.org/view/File:Logo_spdx_250.png" ns="6" title="File:Logo spdx 250.png" />
      <img name="Accessing_SPDX_Licenses_v-2.0.pdf" timestamp="2016-10-12T19:10:21Z" user="Goneall" url="https://wiki.spdx.org/images/Accessing_SPDX_Licenses_v-2.0.pdf" descriptionurl="https://wiki.spdx.org/view/File:Accessing_SPDX_Licenses_v-2.0.pdf" ns="6" title="File:Accessing SPDX Licenses v-2.0.pdf" />
      <img name="SPDX_Matching_Guidelines_AT-JL.docx" timestamp="2016-09-15T17:00:30Z" user="Jlovejoy" url="https://wiki.spdx.org/images/SPDX_Matching_Guidelines_AT-JL.docx" descriptionurl="https://wiki.spdx.org/view/File:SPDX_Matching_Guidelines_AT-JL.docx" ns="6" title="File:SPDX Matching Guidelines AT-JL.docx" />
      <img name="SPDX-2.1.jpg" timestamp="2016-04-01T17:12:12Z" user="Goneall" url="https://wiki.spdx.org/images/SPDX-2.1.jpg" descriptionurl="https://wiki.spdx.org/view/File:SPDX-2.1.jpg" ns="6" title="File:SPDX-2.1.jpg" />
    </allimages>
  </query>
</api>