diff --git a/include/tidyenum.h b/include/tidyenum.h
index 3fd0d07..fb2eff0 100644
--- a/include/tidyenum.h
+++ b/include/tidyenum.h
@@ -619,6 +619,7 @@ typedef enum
   TidyAttr_SIZE,              /**< SIZE= */
   TidyAttr_SPAN,              /**< SPAN= */
   TidyAttr_SRC,               /**< SRC= */
+  TidyAttr_SRCSET,            /**< SRCSET= (HTML5) */
   TidyAttr_STANDBY,           /**< STANDBY= */
   TidyAttr_START,             /**< START= */
   TidyAttr_STYLE,             /**< STYLE= */
diff --git a/src/attrdict.c b/src/attrdict.c
index 7019757..6f072aa 100644
--- a/src/attrdict.c
+++ b/src/attrdict.c
@@ -6451,8 +6451,10 @@ const AttrVersion TY_(W3CAttrsFor_IMG)[] =
   { TidyAttr_OnWAITING,             xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50 },
   { TidyAttr_ROLE,                  xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50 },
   { TidyAttr_SDAPREF,               HT20|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx },
+  { TidyAttr_SIZES,                 xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50 },
   { TidyAttr_SPELLCHECK,            xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50 },
   { TidyAttr_SRC,                   HT20|HT32|H40T|H41T|X10T|H40F|H41F|X10F|H40S|H41S|X10S|XH11|XB10|HT50|XH50 },
+  { TidyAttr_SRCSET,                xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50 },
   { TidyAttr_STYLE,                 xxxx|xxxx|H40T|H41T|X10T|H40F|H41F|X10F|H40S|H41S|X10S|XH11|xxxx|HT50|XH50 },
   { TidyAttr_TABINDEX,              xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50 },
   { TidyAttr_TITLE,                 xxxx|xxxx|H40T|H41T|X10T|H40F|H41F|X10F|H40S|H41S|X10S|XH11|XB10|HT50|XH50 },
diff --git a/src/attrs.c b/src/attrs.c
index 402c637..d95099e 100644
--- a/src/attrs.c
+++ b/src/attrs.c
@@ -227,6 +227,7 @@ static const Attribute attribute_defs [] =
   { TidyAttr_SIZE,              "size",                  CH_NUMBER    }, /* HR, FONT, BASEFONT, SELECT */
   { TidyAttr_SPAN,              "span",                  CH_NUMBER    }, /* COL, COLGROUP */
   { TidyAttr_SRC,               "src",                   CH_URL       }, /* IMG, FRAME, IFRAME */
+  { TidyAttr_SRCSET,            "srcset",                CH_PCDATA    }, /* IMG (HTML5) */
   { TidyAttr_STANDBY,           "standby",               CH_PCDATA    }, /* OBJECT */
   { TidyAttr_START,             "start",                 CH_NUMBER    }, /* OL */
   { TidyAttr_STYLE,             "style",                 CH_PCDATA    },