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="Fig1.38_Packet_Loss_and_Retransmission.gif" />
  </query-continue>
  <query>
    <allimages>
      <img name="ESP_Header_Format.gif" timestamp="2010-03-16T19:31:55Z" url="https://wiki.treck.com/images/9/93/ESP_Header_Format.gif" descriptionurl="https://wiki.treck.com/File:ESP_Header_Format.gif" ns="6" title="File:ESP Header Format.gif" />
      <img name="ESP_Position_in_IPv4_and_IPv6.gif" timestamp="2010-03-16T19:34:27Z" url="https://wiki.treck.com/images/9/94/ESP_Position_in_IPv4_and_IPv6.gif" descriptionurl="https://wiki.treck.com/File:ESP_Position_in_IPv4_and_IPv6.gif" ns="6" title="File:ESP Position in IPv4 and IPv6.gif" />
      <img name="Ethernet_fields_values.gif" timestamp="2010-04-07T17:35:02Z" url="https://wiki.treck.com/images/b/b9/Ethernet_fields_values.gif" descriptionurl="https://wiki.treck.com/File:Ethernet_fields_values.gif" ns="6" title="File:Ethernet fields values.gif" />
      <img name="Ethernet_frame_with_payload.gif" timestamp="2010-04-07T17:33:11Z" url="https://wiki.treck.com/images/f/f8/Ethernet_frame_with_payload.gif" descriptionurl="https://wiki.treck.com/File:Ethernet_frame_with_payload.gif" ns="6" title="File:Ethernet frame with payload.gif" />
      <img name="Ethernet_payload_for_PPPoE.gif" timestamp="2010-04-07T17:36:28Z" url="https://wiki.treck.com/images/5/5f/Ethernet_payload_for_PPPoE.gif" descriptionurl="https://wiki.treck.com/File:Ethernet_payload_for_PPPoE.gif" ns="6" title="File:Ethernet payload for PPPoE.gif" />
      <img name="Fig1.11_ARP_Transmission_Sequence.gif" timestamp="2008-10-03T21:31:48Z" url="https://wiki.treck.com/images/1/1e/Fig1.11_ARP_Transmission_Sequence.gif" descriptionurl="https://wiki.treck.com/File:Fig1.11_ARP_Transmission_Sequence.gif" ns="6" title="File:Fig1.11 ARP Transmission Sequence.gif" />
      <img name="Fig1.12_ARP_Message.gif" timestamp="2008-10-03T21:32:00Z" url="https://wiki.treck.com/images/1/1f/Fig1.12_ARP_Message.gif" descriptionurl="https://wiki.treck.com/File:Fig1.12_ARP_Message.gif" ns="6" title="File:Fig1.12 ARP Message.gif" />
      <img name="Fig1.21_Special_Forms_of_IP_Addresses.gif" timestamp="2008-10-03T21:32:15Z" url="https://wiki.treck.com/images/4/49/Fig1.21_Special_Forms_of_IP_Addresses.gif" descriptionurl="https://wiki.treck.com/File:Fig1.21_Special_Forms_of_IP_Addresses.gif" ns="6" title="File:Fig1.21 Special Forms of IP Addresses.gif" />
      <img name="Fig1.31_Two_Levels_of_ICMP_Encapsulation.gif" timestamp="2008-10-06T19:55:15Z" url="https://wiki.treck.com/images/0/0e/Fig1.31_Two_Levels_of_ICMP_Encapsulation.gif" descriptionurl="https://wiki.treck.com/File:Fig1.31_Two_Levels_of_ICMP_Encapsulation.gif" ns="6" title="File:Fig1.31 Two Levels of ICMP Encapsulation.gif" />
      <img name="Fig1.37_Simple_Positive_Acknowledgment_with_Retransmission.gif" timestamp="2008-10-06T19:55:29Z" url="https://wiki.treck.com/images/5/50/Fig1.37_Simple_Positive_Acknowledgment_with_Retransmission.gif" descriptionurl="https://wiki.treck.com/File:Fig1.37_Simple_Positive_Acknowledgment_with_Retransmission.gif" ns="6" title="File:Fig1.37 Simple Positive Acknowledgment with Retransmission.gif" />
    </allimages>
  </query>
</api>